Rivet Joint, sure the country is in desperate need of homes but development needs to be sustainable, and that includes provision of employment. Passengers are only one aspect of airports, suggesting building on them because they don't have extensive route networks to major cities as you imply by your statement is foolish. The same argument could otherwise apply to any office outside Canary Wharf/City of London, any shop not run by a major chain or in a large shopping centre etc.