TigerDirect, it was only $20! They're everywhere now and have all kinds of capabilities. I don't need to run a reciprocating saw off of my car, so I got the simple Xantrex 100, it weighs less than half a pound and they have even more compact ones than that. For $20, I am thrilled with it and it works perfectly.

My battery is beginning to show its age too, and a new one is $120, so for me, this is ideal.

Out on the net, you can find charts that show which planes/airlines have power outlets in the seats. Most are in business & 1st class, but I have the miles, and I'm worth it!