i have to agree with what's been said above, i dont think you'd make much at all just doing it weekends, especially as most exec travel is demand, whereby you are on call 24-7 and not just weekends

you'd be better off (as already stated) doing airport runs in a mini bus, carting big families to & from airports

i did have a quick look today at old luxury cars, cant believe how cheap some are now, look at the prices of S320 mercs! £3k for a motor that cost £60k new