Examples of use of up in the air
1. "There are several questions still up in the air.
2. "Things are very much up in the air." See also...
3. Left up in the air is the fate of Bush‘s visit to South Korea.
4. "When they were up in the air, they thought something was not right," Maria Nihlen said.
5. But just being left up in the air means it is very difficult.