Historical clue formulations

• Their prospects are up in the air — 2020-01-13
• Ones doing loops and barrel rolls — 2019-07-30
• What drones lack — 2018-01-28
• Flap raisers? — 2000-10-06
• Lackland trainees — 1996-09-14
• American workers — 1996-02-25
• Northwest workers — 1994-11-20