Editing Transatlantic flight (section)

===Commercial aeroplane service attempts===

It would take two more decades after Alcock and Brown's first nonstop flight across the Atlantic in 1919 before commercial airplane flights became practical. The North Atlantic presented severe challenges for aviators due to weather and the long distances involved, with few stopping points. Initial transatlantic services, therefore, focused on the South Atlantic, where some French, German, and Italian airlines offered [[seaplane]] service for mail between South America and West Africa in the 1930s.

Between February 1934 and August 1939 [[Deutsche Luft Hansa|Lufthansa]] operated a regular airmail service between [[Natal, Rio Grande do Norte|Natal, Brazil]], and [[Banjul|Bathurst, Gambia]], continuing ''via'' the [[Canary Islands]] and Spain to [[Stuttgart]], Germany.<ref>{{Cite book |last1=Graue |first1=James W. |title=Deutsche Lufthansa, South Atlantic Airmail Service: 1934 - 1939 |last2=Duggan |first2=John |date=2000 |isbn=978-0-9514114-5-2 |series=Zeppelinpost Handbook |location=Ickenham}}</ref> From December 1935, [[Air France]] opened a regular weekly airmail route between South America and Africa. German airlines experimented with mail routes over the North Atlantic in the early 1930s, with flying boats and dirigibles. 

In August 1938<ref>{{cite web | url=https://www.thisdayinaviation.com/10-11-august-1938/ | title=10–11 August 1938 &#124; This Day in Aviation | date=10 August 2023 }}</ref> a [[Deutsche Luft Hansa]] [[Focke-Wulf Fw 200 Condor]] long-range airliner flew non-stop from<ref>{{cite web | url=https://www.youtube.com/watch?v=m0K28_SOFzw | title=Focke-Wulf Fw 200 Condor record flight between Berlin and New York in 1938 | website=[[YouTube]] | date=8 May 2020 }}</ref> Berlin [[Floyd_Bennett_Field#Notable_flights|to New York]] and returned non-stop as a proving flight for the development of passenger-carrying services. This was the first landplane to fulfil this function and marked a departure from the British and American reliance on flying boats for long over-water routes.<ref>Karl-Dieter Seifert "Der Deutsche Luftverkehr 1926–1945" Bernard & Graefe Verlag, Bonn 1996 {{ISBN|3-7637-6118-7}} (in German) p. 303–304</ref> Operators of the Fw 200 focussed on other routes, though.

==== Flying boats ====
[[File:Consolidated PBY Catalina landing at Naval Air Station Jacksonville, Florida (USA), circa in 1943.jpg|thumb|Flying boats were used for transatlantic flights in the 1930s|right]]
[[File:Seaplanes at Foynes.jpg|thumb|left|[[Foynes]], [[Ireland]] was the European terminus for all transatlantic flying boat flights in the 1930s.]]

In the 1930s a flying boat route was the only practical means of transatlantic air travel, as land-based aircraft lacked sufficient range for the crossing. An agreement between the governments of the US, Britain, Canada, and the [[Irish Free State]] in 1935 set aside the Irish town of [[Foynes]], the most westerly port in [[Ireland]], as the terminal for all such services to be established.<ref name="History Ireland">{{cite web|url=http://www.historyireland.com/troubles-in-ni/ni-1920-present/the-flying-boats-of-foynes/|title=The Flying Boats of Foynes|date=11 February 2013|publisher=History Ireland|access-date=19 June 2014|archive-url=https://web.archive.org/web/20140604114900/http://www.historyireland.com/troubles-in-ni/ni-1920-present/the-flying-boats-of-foynes/|archive-date=4 June 2014|url-status=live}}</ref>

[[Imperial Airways]] had bought the [[Short Empire]] flying boat, primarily for use along the [[British Empire|empire]] routes to Africa, Asia and Australia, and had established an international airport on [[Darrell's Island, Bermuda|Darrell's Island]], in the [[Imperial fortress]] [[British Overseas Territory|colony]] of [[Bermuda]] (640 miles off [[Cape Hatteras]], [[North Carolina]]), which began serving both Imperial Airways, subsequently renamed [[British Overseas Airways Corporation]] (BOAC) and [[Pan American World Airways]] (PAA) flights from the United States in 1936,<ref>{{cite book |last=Partridge and Singfield |first=Ewan and Tom|author-link= |date=2014 |title=Wings Over Bermuda: 100 Years of Aviation in the West Atlantic |url=https://nmb.bm/ |location=[[Royal Naval Dockyard, Bermuda]], Ireland Island, Sandys Parish, Bermuda |publisher=National Museum of Bermuda Press |page= |isbn=9781927750322}}</ref> but began exploring the possibility of using it for transatlantic flights from 1937. PAA would begin scheduled trans-Atlantic flights via Bermuda before Imperial Airways did,<ref>{{cite book |last=Pomeroy |first=Squadron Leader Colin A. |author-link= |date=2000 |title=The Flying Boats Of Bermuda |url= |location=Hamilton, Pembroke, Bermuda|publisher=Printlink Ltd |page= |isbn=9780969833246}}</ref> enabling the United States Government to covertly assist the British Government before the United States entry into the Second World War as mail was taken off trans-Atlantic PAA flights by the Imperial Censorship of [[British Security Co-ordination]] to search for secret communications from Axis spies operating in the United States, including the [[Kurt Frederick Ludwig#Setting up the ring|Joe K ring]], with information gained being shared with the [[Federal Bureau of Investigation]].<ref>{{Cite news |first=Tim |last=Hodgson |url=https://www.royalgazette.com/other/news/article/20160425/celebrating-a-wartime-spy-chief |title=Celebrating a wartime spy chief |work=The Royal Gazette |location=City of Hamilton, Pembroke, Bermuda |access-date=2022-07-23}}</ref><ref>{{cite web |url=http://www.fairmont.com/hamilton-bermuda/hotel-history |title=Hotel History of the Fairmont Hamilton Princess |author=<!--Not stated--> |website=Fairmont Hamilton Princess Hotel (Princess Hotel) |publisher=Fairmont Hotels & Resorts |access-date=2022-07-23}}</ref><ref>{{cite news |author=<!--not stated--> |date=2011-11-11 |title=Bermuda's WWII Espionage Role |url=http://bernews.com/2011/11/bermudas-second-world-war-espionage-role |work=BERNEWS |location=Bermuda |access-date=2022-07-23}}</ref> The range of the Short Empire flying boat was less than that of the equivalent US [[Sikorsky S-42|Sikorsky "Clipper" flying boats]] and as such was initially unable to provide a true trans-Atlantic service.<ref name="History Ireland"/>

Two flying boats (''Caledonia'' and ''Cambria'') were lightened and given long-range tanks to increase the aircraft's range to {{convert|3300|mi}}.

In the US, attention was at first focused on transatlantic flights for a faster postal service between Europe and the United States. In 1931 W. Irving Glover, the second assistant postmaster, wrote an article for ''[[Popular Mechanics]]'' on the challenges and the need for a regular service.<ref>[https://books.google.com/books?id=u-IDAAAAMBAJ&dq=Popular+Mechanics+1931+curtiss&pg=PA186 "Wings Across The Atlantic."] {{Webarchive|url=https://web.archive.org/web/20140129162830/http://books.google.com/books?id=u-IDAAAAMBAJ&pg=PA186&dq=Popular+Mechanics+1931+curtiss&hl=en&ei=2kTvTOz_A6HfnQfR0_C7Cw&sa=X&oi=book_result&ct=result&resnum=3&sqi=2&ved=0CC8Q6AEwAg#v=onepage&q&f=true |date=29 January 2014 }} ''Popular Mechanics'', March 1931.</ref> In the 1930s, under the direction of [[Juan Trippe]], [[Pan Am]]erican began to get interested in the feasibility of a transatlantic passenger service using flying boats.

[[File:Airplane. Captain Wilcockson Signs Autograph BAnQ P48S1P01041.jpg|thumb|right|Captain Wilcockson signing an autograph for one of his admirers, in July 1937, near [[Montreal, Quebec]].]]

On 5 July 1937, A.S. Wilcockson flew a [[Short Empire]] for [[Imperial Airways]] from Foynes to [[Botwood]], [[Newfoundland]] and Harold Gray piloted a [[Sikorsky S-42]] for Pan American in the opposite direction. Both flights were a success and both airlines made a series of subsequent proving flights that same year to test out a variety of different weather conditions. [[Air France]] also became interested and began experimental flights in 1938.<ref name="Gandt">Gandt, Robert L. ''China Clipper—The Age of the Great Flying Boats''. Annapolis, Maryland: Naval Institute Press, 1991. {{ISBN|0-87021-209-5}}.</ref>

As the Short Empire only had enough range with enlarged fuel tanks at the expense of a passenger room, several pioneering experiments were done with the aircraft to work around the problem. It was known that aircraft could maintain flight with a greater load than is possible to take off with, so Major Robert H. Mayo, Technical general manager at [[Imperial Airways]], proposed mounting a small, long-range seaplane on top of a larger carrier aircraft, using the combined power of both to bring the smaller aircraft to operational height, at which time the two aircraft would separate, the carrier aircraft returning to base while the other flew on to its destination.<ref name="History Ireland"/>

The [[Short Mayo Composite]] project, co-designed by Mayo and Shorts chief designer Arthur Gouge,<ref name="Barnes">{{cite book|author=Barnes C.H.|title =Shorts Aircraft since 1900|year =1989|publisher =Putnam|location =London|isbn = 0-85177-819-4|page =560}}</ref><ref>"[http://www.flightglobal.com/pdfarchive/view/1962/1962%20-%202457.html World News: Sir Arthur Gouge] {{Webarchive|url=https://web.archive.org/web/20141028210952/http://www.flightglobal.com/pdfarchive/view/1962/1962%20-%202457.html |date=28 October 2014 }}". ''Flight International'', 25 October 1962, page 660</ref> comprised the ''Short S.21 Maia'',<ref name="maia">Named for [[Maia (mythology)|Maia]], the Greek goddess and mother of [[Hermes]], messenger of the Gods, while Hermes was known to the Romans as [[Mercury (mythology)|Mercury]]</ref> (''G-ADHK'') which was a variant of the [[Short Empire|Short "C-Class" Empire]] flying-boat fitted with a trestle or pylon on the top of the fuselage to support the ''Short S.20 Mercury''(''G-ADHJ'').<ref name="maia"/><ref>Flight 19 August 1937 p180</ref>

The first successful in-flight separation of the ''Composite'' was carried out on 6 February 1938, and the first transatlantic flight was made on 21 July 1938 from [[Foynes]] to [[Boucherville]].<ref>[http://www.borstal.org.uk/history/shorts.shtml Also contains an eye-witness account of the first in-flight separation] {{webarchive|url=https://web.archive.org/web/20081118194510/http://www.borstal.org.uk/history/shorts.shtml |date=18 November 2008 }}</ref> ''Mercury'', piloted by Captain [[Don Bennett]],<ref>Captain Bennett was later the first commander of the RAF [[Pathfinder Force]] in World War II and became an [[Air Vice Marshal]]</ref> separated from her carrier at 8&nbsp;pm to continue what was to become the first commercial non-stop east-to-west transatlantic flight by a [[heavier-than-air]] machine. This initial journey took 20 hrs, 21 min at an average ground speed of {{convert|144|mph}}.<ref>[http://www.flightglobal.com/pdfarchive/view/1938/1938%20-%202137.html "Mercury makes good"] {{Webarchive|url=https://web.archive.org/web/20131215093439/http://www.flightglobal.com/pdfarchive/view/1938/1938%20-%202137.html |date=15 December 2013 }} ''Flight'' 28 July 1938. pp. 79–80</ref>

Another technology developed for transatlantic commercial flight was [[aerial refuelling]]. Sir [[Alan Cobham]] developed the ''Grappled-line looped-hose'' system to stimulate the possibility for long-range transoceanic commercial aircraft flights,<ref>{{Cite web |url=http://www.flightglobal.com/pdfarchive/view/1947/1947%20-%200392.html |title='' "Refueling In Flight" '', Flight magazine, 1947 |access-date=19 June 2014 |archive-url=https://web.archive.org/web/20150402160634/http://www.flightglobal.com/pdfarchive/view/1947/1947%20-%200392.html |archive-date=2 April 2015 |url-status=live }}</ref> and publicly demonstrated it for the first time in 1935. In the system, the receiver aircraft trailed a steel cable which was then grappled by a line shot from the tanker. The line was then drawn back into the tanker where the receiver's cable was connected to the refueling hose. The receiver could then haul back in its cable bringing the hose to it. Once the hose was connected, the tanker climbed sufficiently above the receiver aircraft to allow the fuel to flow under gravity.<ref>{{Cite book |url=https://books.google.com/books?id=KSYDAAAAMBAJ&q=popular+science+1947+%22Faster,+huskier,+and%22&pg=RA2-PA82 |title="Gas Station In The Sky" '', January 1947,'' Popular Science |date=January 1947 |access-date=20 October 2016 |archive-url=https://web.archive.org/web/20140617204831/http://books.google.com/books?id=KSYDAAAAMBAJ&pg=RA2-PA82&dq=popular+science+1947+%22Faster,+huskier,+and%22&hl=en&ei=oqbbTMb-MdH_nQegvNAW&sa=X&oi=book_result&ct=result&resnum=1&ved=0CC0Q6AEwAA#v=onepage&q&f=true |archive-date=17 June 2014 |url-status=live }}</ref><ref>[http://www.flightglobal.com/pdfarchive/view/1945/1945%20-%202295.html?search=Flight%20Refuelling "Refuelling In Flight", ''Flight Magazine'', 22 November 1945] {{Webarchive|url=https://web.archive.org/web/20131005123217/http://www.flightglobal.com/pdfarchive/view/1945/1945%20-%202295.html?search=Flight%20Refuelling |date=5 October 2013 }} close-up drawing of receiver pawl grapnel and tanker haul line projectile</ref>

Cobham founded [[Flight Refuelling Ltd]] in 1934 and by 1938 had demonstrated the ''FRL's looped-hose'' system to refuel the [[Short Empire]] flying boat ''Cambria'' from an [[Armstrong Whitworth AW.23]].<ref>''History of Aviation'', Part 19, 1938</ref> [[Handley Page H.P.54 Harrow|Handley Page Harrows]] were used in the 1939 trials to aerial refuel the Empire flying boats for regular transatlantic crossings. From 5 August – 1 October 1939, sixteen crossings of the Atlantic were made by Empire flying boats, with 15 crossings using FRL's aerial refuelling system.<ref>Note&nbsp;– on one flight there was a high westerly wind and no need for aerial refuelling </ref> After the 16 crossings more trials were suspended due to the outbreak of World War II.<ref>{{Cite web |url=http://www.flightglobal.com/pdfarchive/view/1940/1940%20-%201219.html?search=Flight%20Refuelling |title='' "Refuelling In Flight" '', Flight magazine, 25 August 1940 |access-date=19 June 2014 |archive-url=https://web.archive.org/web/20131005122815/http://www.flightglobal.com/pdfarchive/view/1940/1940%20-%201219.html?search=Flight%20Refuelling |archive-date=5 October 2013 |url-status=live }}</ref>

The [[Short S.26]] was built in 1939 as an enlarged [[Short Empire]], powered by four 1,400&nbsp;hp (1,044&nbsp;kW) [[Bristol Hercules]] sleeve valve radial engines and designed with the capability of crossing the Atlantic without refuelling. It was intended to form the backbone of [[Imperial Airways]]' Empire services. It could fly {{convert|6000|mi}} unburdened, or 150 passengers for a "short hop".<ref name=flight1939-59>{{citation |title=The Biggest Short |url=http://www.flightglobal.com/pdfarchive/view/1939/1939-1-%20-%200196.html |journal=Flight |date=20 July 1939 |page=59 |access-date=19 June 2014 |archive-url=https://web.archive.org/web/20140714130903/http://www.flightglobal.com/pdfarchive/view/1939/1939-1-%20-%200196.html |archive-date=14 July 2014 |url-status=live }}</ref> On 21 July 1939, the first aircraft, (G-AFCI "Golden Hind"), was first flown at Rochester by Shorts' chief [[test pilot]], [[John Lankester Parker]]. Although two aircraft were handed over to Imperial Airways for crew training, all three were impressed (along with their crews) into the [[RAF]] before they could begin civilian operation with the onset of [[World War II]].

[[File:Boeing 314 Yankee Clipper 1939.jpg|left|thumb|The ''[[Boeing 314 Clipper|Yankee Clipper]]'' in 1939.]]

Meanwhile, Pan Am bought nine [[Boeing 314 Clipper]]s in 1939, a long-range [[flying boat]] capable of flying the [[Atlantic]].<ref name=Follett>{{cite book |chapter=Author's Note |title=Night over water|url=https://archive.org/details/nightoverwater00kenf |url-access=registration |page=[https://archive.org/details/nightoverwater00kenf/page/399 399] |author-link=Ken Follett |first=Ken |last=Follett|isbn=0-688-04660-6 |lccn=91017701|publisher=[[William Morrow and Company]]|location=New York |year=1991}}</ref> The "Clippers" were built for "one-class" luxury air travel, a necessity given the long duration of transoceanic flights. The seats could be converted into 36 bunks for overnight accommodation; with a cruising speed of only {{convert|188|mph|km/h}}. The 314s had a lounge and dining area, and the galleys were crewed by chefs from four-star hotels. Men and women were provided with separate dressing rooms, and white-coated stewards served five and six-course meals with gleaming silver service.<ref name="travelscholar">[http://www.travelscholar.com/concorde/ "British Airways Concorde."] {{Webarchive|url=https://web.archive.org/web/20060523202342/http://www.travelscholar.com/concorde/ |date=23 May 2006 }} ''Travel Scholar'', Sound Message, LLC. Retrieved: 19 August 2006.</ref>

The ''Yankee Clipper'''s inaugural trip across the Atlantic was on 24 June 1939. Its route was from [[Southampton]] to [[Port Washington, New York]] with intermediate stops at [[Foynes|Foynes, Ireland]], [[Botwood, Newfoundland and Labrador|Botwood, Newfoundland]], and [[Shediac|Shediac, New Brunswick]]. Its first passenger flight was on 9 July, and this continued only until the onset of the [[Second World War]], less than two months later. The ''Clipper'' fleet was then pressed into military service and the flying boats were used for ferrying personnel and equipment to the [[European theatre of World War II|European]] and [[Pacific Theatre of World War II|Pacific fronts]].