[soperj]

After they land, they usually sit around for a while. Not really super important to charge the battery on decent I wouldn't think. Would be interesting to get rid of the battery entirely (or reduce the size) and have a beefed up magsafe plug that was attached during lift off, and came unplugged once it was at cruising altitude.

[Melatonic]

At that point seems like you might as well use a launch system like aircraft carriers use

[ssl-3]

That would certainly help get the aircraft up to a speed where it has usable lift and can leave the ground. That's a good headstart, and it represents a significant amount of energy.

A catapult launch can't help with the next 30,000 feet of climbing, though, while the impossible umbilical might.