in flight
In the act of flying. Can also be hyphenated and used to describe something offered or done while one is traveling by airplane. Look at those geese in flight! Luckily, the baby fell asleep in flight and didn't wake up till we landed in Dallas. Remember when there used to be an in-flight movie? Geez, those were the days.
in flight
while flying. A passenger became ill in flight and the pilot had to return to the airport. I really don't care to eat in flight. I am too nervous.