I fly the C42 and EV97 microlights and know several instructors, all effectively self employed, whether that is tied to a school or in effect running their own school with their own aircraft. None of them earn a fortune that's for sure.
In terms of costs, it really can vary wildly in relation to the cost of locating the business/aircraft as parking/hangarage costs can vary so much. Operating costs are more straightforward. Work on 15L ph of Mogas for fuel = £16, roughly £10 per tacho hour over the life of the Rotax engine before it needs replacement/overhaul, plus the cost of the 25/50 hr checks and Permit. Then there's insurance - not sure on costs but bound to be a fair sum pa for training.
And of course there's the capital outlay for the aircraft. A good C42 may cost £25-30K which could be several hundred £££ pcm in any finance payment.
All in all; parking/hangarage, insurance, maintenance, a few inevitable repairs, fuel, finance, perhaps the cost of adverstising your services... that's a lot of hours of instruction every month you have to do before you break even.
If it's microlights you are looking at, get the NPPL, build the required hours, do the microlight AFI course and build some instructional hours - then re-assess the situation!
ETA - the few people I know who do run a one man band outfit have normally been in the industry for years and have a well established reputation and the contacts that come with that.
Last edited by XXPLOD; 22nd August 2009 at 15:08.