[Hugh]

This is a 1943 First Flight cover from Oranjestad, Aruba to Miami ... and on to Falls Church, Virginia.

Stamp: Curacao [Curaçao]
Queen Wilhelmina / Airplane over the Atlantic Ocean
Luchtpost [Airmail]
Issued on October 20, 1942
35c, Dark Violent / Olive Green
NVPH LP35 / Sc. C23

Cancels:
Receiving Cancel: Double ring CDS with bar, black ink
+ ARUBA + / ORANJESTAO
[1?]6.8.43
I'm assuming there is a missing '1' in the data (there is a hint of ink) as the recorded date of this flight was August 16.

Arrival Cancel: Double ring, purple ink (on reverse)
FALLS CHURCH, VA / PARCEL POST
AUG / 23 / 1943

Auxiliary Markings:

Censor Mark: Curaçao
Hand-stamp, purple ink, 23mm
GEZIEN / CURACAO / CENSUUR [SEEN / CURACAO / CENSORSHIP]
Sealed with buff tape: EXAMINED BY 1889

KLM Cachet 1 - Printed on Cover, red and blue printing
KLM / Royal Dutch Airlines
Willemstad - Curaçao
New York, U.S.A
Lichtpost - Air Mail
Between the crossed US and Dutch Flags is a V and a dot-dot-dot-dash [Morse code for V = Victory]

First Flight Cachet 2 - On Reverse, hand-stamped, green ink.
Outer rim = EERSTE OFFICIEELE VLUCHT
Ribbon above route panel = FIRST OFFICIAL FLIGHT
Route panel CURAÇAO USA / WILLEMSTAD - ARUBA - HAITI / JAMAICA - CUBA / MIAMI FLORIDA
Centre image: Faint, but appears to be a plane over the Caribbean. I used an app called Image Sleuth to help bring out the faint elements of the cachet.