Question On Airmail FDC, Washington To England

Good afternoon all,
Yesterday I picked up a few items at a local flea market, including this one.



I can't find any information on the actual flight this cover is supposed to be marking. The cover is a little tatty, and seems to have had a label at bottom left, below the date, that has been removed.
I suspect this a home-made cover. Does anyone have any information on the flight in question? Thanks in advance.
Regards
DavidR

It can't be a FDC. The stamp was issued May 19, 1938 in Philadelphia and May 20, 1938 in DC. And 1 1/2 cents was not enough postage for a letter to England. I can't tell you anything about the flight.

It looks like it might be missing stamps at upper left.

Thanks chaps. I realise it is not a FDC for the prexie, and pretty sure there is nothing at top left but some creasing. There is definitely something missing from bottom left. The inscription on the envelope could be hand written, but is in raised ink so not too sure. Thought it might be for a specific flight out of Washington but cannot find anything.
Regards
DavidR

The 30 cent Trans-Atlantic airmail stamp Scott C24 was issued May 16, 1939 in New York City.
May 17, 1939 would have been the first day of sale everywhere else.
The Postal Bulletins provide instructions for collectors desiring FDCs as well as First Flight Covers (both from NYC).

Regardless, the sender used the envelope (probably as a remainder) as an unsealed 3rd class cover, franked properly at 1.5 cents and which received an undated parcel post style roller cancel. With the original intent being a flight cover, it originally had an airmail etiquette label at the lower left, which was removed by the sender before he could use it later for a non-airmail purpose. The cover may have been mailed many days or months after the date in the cachet as a way or using up an obsolete cover.

Thanks John Becker, that all makes sense.
Regards
DavidR

Well, that's my guess/interpretation. Others may see it differently, but there seemed to be two facets: the original intent of the cachet and how it was actually used.