I'll cross post this in the US covers.
I have a US First Flight (FAM 27-3). The few I could find on line are all virtually identical in cancels to this one EXCEPT for the Cairo machine cancel that ties the US Christmas seal on the reverse. The receiving Cairo cancel is 3 April 46; and the machine cancel is 25 April 46.
Was this a forwarding cancel back to the sender? I assume the Station Manger in the address would have received this directly at the airport.
Why the three-week span between the two cancels? And the purpose of the second Cairo cancel. Am I missing an Egyptian stamp on the reverse that would explain this?