A Loophole?

Nope. Not really.

Reader Charles Grimm emails with a question regarding passengers in spacecraft:

I read the writeup on Rutan’s vehicle in AvLeak, and had a
question: Rutan can take no paying customers in his craft, but private
aircraft owners can share costs of a flight (fuel, oil, I’m not sure whatever
else) with passengers even if they’re not allowed to take paying customers. I
can reimburse a friend for the cost of gas when he flies his plane to keep his
hours up. Could a prospective passenger fork over the cost of the rocket fuel,
to help defray Rutan’s expenses?

Yes, probably, but you couldn’t make a business out of that. Fuel will be a small part of the total expenses. If he just wants to give people rides, he can do so (assuming he gets a launch license), but he’d never make any money at it, and in fact he (or whoever hired him to build it) would lose money.