When you are uncertain about your weekend plans, there are two common phrases.
The first phrase is “To play it by ear“. This phrase means to improvise and comes from the world of music. If a musician doesn’t have the written music to play a particular song, she must listen carefully and try to reproduce it “by ear”. For this reason, “to play it by ear” means to invent something as you go. Since there are many situations like this in life, it isn’t surprising that we apply this phrase to more than just music.
A: What are you doing this weekend?
B: I have no idea; I guess I’ll just play it by ear.
The second phrase is “up in the air“. The origin of this phrase couldn’t be found, but the meaning seems to be relaltively intuitive. Objects that are “up in the air” haven’t landed yet so their final position hasn’t been determined. If your plans are “up in the air” you haven’t made your decision yet.
A: What are you doing this vacation?
B: I don’t know we’ve seen some cheap airfare to exotic destinations, there is some pressure to visit family, but really we just want to relax at home for a few days – basically everything is still up in the air.