Such cameras were the only choice not that long ago and plenty of good photos were obtained and there are still many people using film. If the camera's mechanically sound and the metering works then give it a go.
As said, it will give you a handle on what photography's about. In some respects a digital camera may be more immediately useful because you see the effects of shutter/aperture/exposure compensation, etc straight away rather than having to wait to have the film developed.
There are plenty of 2nd hand shops/Ebay and the like that will have lenses for the Minolta MD
mount camera. For an airshow with aircraft on the ground you'll probably need a wide angle to short telephoto - say 24-135mm range of focal length. For aircraft landing/taking off... 100-400mm. At least with a 2nd hand lens you can buy it, try it for a while and resell it for little loss, I'd have thought.
As with digital, the quality of the image depends a lot on the quality of the lens, though the exposure/metering will be affected by the camera and photographer's experience (knowing the "rules" of exposure - shoot with the sun behind you, beware white aircraft can confuse meters, as can dark aircraft)