Short term I have several battery air pumps, a couple are the ones that plug in to the 120v wall outlet and come on on battery when they sense a power outage.
For longer term I have a Champion 3500w generator. Its on wheels and can be moved around easily. I store it with a couple extension cords and outlet strips tied to the frame so they don't get legs and the tank is always full with a litte StaBil in it so the gas does not go bad.
It starts first time every time ane even the wife can start it easily.
I did a lot of research before buying and purchased this one on the recommendations from www.RV.net where it is very popular. Thye carry them at Checker/Schucks/Kragen/Murrays/O'Reillys Auto Parts, Parts America and Cabellas as well as some Sams and Costcos. I paid $238 on sale and with a calendar coupon and price match and its one of the best investments I have ever made.