flight record; endurance record (in the air)
Refers to a record for the longest time spent continuously in the air, typically by an aircraft, bird, or flying object.
The airplane broke the flight endurance record.
The flight endurance records of migratory birds are astonishing.
飛行記録 is a broader term for any flight log or record of a flight, while 滞空記録 specifically refers to a record of time spent aloft (endurance).
Compound of 滞空 (たいくう, 'staying in the air') and 記録 (きろく, 'record').