【in the air】 —

1. not inside a house or building:

• We have taken our last walk 【in the air】 and having succeeded in tiring ourselves feel free to go to bed unashamed.

2. aboard an aircraft; in flight:

• After all, Short’s Empire class flying boats fifty years ago could offer a bed 【in the air】 .

3. (of plans, questions, etc.) still uncertain; remaining undecided:

• As for other ever changing events, next year’s plans are still 【in the air】 .

4. (also: in the wind) rumored or suspected but not definitely known:

• What changes they will make nobody knows, but there is something 【in the air】 .

5. said of the general mood or atmosphere:

• There was a feeling of joy 【in the air】 . Men who had never voted before said that they felt like human beings for the first time in their lives.

6. (of military position) uncovered or unprotected:

• This left the French First Army’s flank 【in the air】 , forcing it to withdraw as well.

Note: The expression does not fully correlate in meaning with the phrase in the open air—

1. = 【in the air】 1:

• In the early evening Ernest went to speak to a group of the neighboring inhabitants in the open air.

2. unsheltered or unprotected from the elements:

• I myself saw new motors and parts piled up unprotected in the open air.

【up in the air】 —

1. = 【in the air】 2:

• If you’re up 【in the air】 and something goes wrong, you pull that parachute, and the whole plane goes down slowly.

2. = 【in the air】 3:

• Our plans for a vacation are still up 【in the air】 , but we’ll be going sometime after the new year.

3. (coll.) angry; excited:

• He is all up 【in the air】 because he had to wait a few minutes.

Note: Neither expression correlates in meaning with the phrase on the air—

1. speaking over the radio:

• If Bucky Maynard doesn’t like you, you got a lot of trouble. I mean, he can destroy you on the air.

2. (of a program) being broadcast:

• McGannon is asking that stations be obliged to set aside a time when only children’s programs would be allowed on the air.