It's impossible to answer your question directly.
MacBook Airs have gone through several generations. The original MacBook Air uses the MagSafe charger. This is not compatible with anything other than a MacBook (standard, Pro or Air) that has the corresponding MagSafe charger socket.
The latest generation of MacBook Air charges via USB-C, and ships with a USB-C charger. This charger can be used to charge your iPhone, with an appropriate USB-C to Lightning charger cable.
Since you don't identify the generation of your MacBook Air, or the charger it came with, I can't advise which of these options applies to you. Hopefully, though, there's enough here that you can work it out.