If the local council chooses to give planning permission for houses to be built, they will need to be very very careful to ensure that the money Peel get from the house building is formally tied to the continued operation of a public use airport and all the infrastructure that goes with an airport (e.g. fire cover, ATC, etc...). If Peel were to break the link, the clause should stipulate some significant penalty that Peel must pay to the council.
Without a formal linkage, it would be very easy for Peel to take the money from selling the homes, and then after 3 years say that actually the airport still isn't viable anyway and want to sell more land for other development. 200 more houses, then another 300 more houses, then another 100 more houses, etc etc....
The result would be substantially uncontrolled development of the land and the loss of a commercial airport.
The alternative is for the council to admit the airport is non viable right now, and let the whole airport site be redeveloped on a large scale in a controlled way that substantially benefits the local area and residents.