Hi there. I understand why you might be confused. How doctors treat an non-displaced fracture of fifth metatarsal varies a bit, there are no hard and fast rules. My own view would be that a good supporting shoe or boot for 2 weeks would be sufficient. An air-cast for a further 4 weeks would, again in my view, be overkill.
Listen to your body and rest that foot as much as is practical. Avoid doing things that are hurting your foot. The among of pain/discomfort that you are experiencing will tell you more than any doctor. When you are pain-free then you know all is well. There are no great risks into the future from a fractured metatarsal
. Good luck, mind yourself.