Good proposal, and one that has worked for many microlight instructors, including me.
Buying a plane is not a big expense - but leasing is how many many businesses do it, whether flying schools or driving schools.
In microlights, it is almost impossible to lease, so we buy. In the case of my Ikarus, 45k or my weighshift at 25k (new prices). That is a bhig expense.
I started in a farmer's field with a portacabin. I then went to Cumbernauld Airport for six years. Then I bought a farmer's field (Strathaven, which happened to get planning permission as an airfield 50 years ago!).
The situation at Cumbernauld was how you imagined it. I went to the airfield operator and said I wanted to base a microlight there and start training.
The airfield provided a runway, hangar space, a tower (with met stuff etc) and a public waiting room and a public briefing room (for visiting pilots to use, among other things, like me!).
I had a microlight, a briefcase with student records and briefing notes, a car with a box of logbooks and textbooks for sale, and a mobile phone. At home, I had a computer and office.
It only made sense to work from one airfield since the travelling time - even by air - wasn't chargeable.
If the microlight was off being serviced or I was on holiday - strange how the two get combined! - then no students flew. Since the nearest microlight school was 50 miles away, this was not a problem. If you have a one-to-one relationship with students, they understand things in a different way to when you are a part of a bigger organisation. You want to hear of their holidays, they want to hear of yours!
If the microlight was trashed in a crash, as happened, then I just had to buy a replacement. My credit card has a 15k limit on it!! So out of service for a week or so.
If students were solo on the school aircraft, I got a break from being in the air and still made money. Maybe I could have made more by having another aircraft in the air at the same time, but I would have had more costs, could only have been in the circuit and wouldn't have been able to take notes on all their solo circuits to debrief them.
(as an aside, anyone know of anyone who videos students' landings?)
Now I have my own field, I have two instructors working with me - on a franchise basis, and one is also a driving instructor, so knows the score on that front too.
I now have to provide the airfield services etc and answer the phone. It is amazing how many people I probably missed at Cumbernauld - but then I still had enought business for lonely me with the ones that persevered!
And then there are the dark wet winter months to get all your paperwork and tax returns sorted.
If you don't want to be a career instructor, then let someone else have all the hassle and work for a flying school. You won't get paid much.
If you want to work for yourself, and have all the hassle, you can do it. But you won't get paid much once you take into account all the expenses (your income is determined by what the other flying schools charge, in the main, and since they pay their instructors very little, your business plan will have to have YOU paid very little).
If you are a success, you will then take on other instructors - and then you'll stop flying because you'll be handling all the paperwork (which will have exploded exponentially!). And you still won't get paid much because - having been there - you'll want to make sure your " career" instructors stay with you, since if you have no instructors you'll have no income, so you'll try and give them fair pay.
And then someone crashes your 45k Ikarus at the height of the flying season, as someone did last week with me. So no aircraft and an insurance claim in - and so can't just say, get it repaired NOW. It may be October before it is repaired/written off. And there is a two month waiting list for a new aircraft and no second hand ones around - even if I wanted to take the cash for the new hangar and spend it on a replacement aircraft to keep us flying.
Why do we do it? We must be masochists if we say it is because we love it!
It boils down to: if you want to instruct, get a job as a flying instructor.
If you want to run a flying school, run a flying school (but you'd be lucky to do much flying if you try and expand, and the temptation will be there)
Yes, there is a halfway house. That is to be a freelance one-man band. And there can be happy, workable niches. Loook at that chap Derek who advertises the one week and pass all your JAR PPL exam courses, for example.
So, why so few people doing it? It is a special niche, not attractive or workable to many people.
Very best wishes, and good luck.