Happy to answer any questions out there about this since we just did it at my airport. We are a quasi-governmental entity, so yes, tons of red tape. Also, building hangars with grant money is not the same as building them as a private entity. You can do it at about 1/3 to 1/2 the cost it took us to build the same structure...maybe even better. To do the site prep and build our recent 10 unit T-hangar building cost in the ballpark of $1 million. These are very basic, with their only fringe benefit being electric bi-fold doors.
There is also the matter of what to charge for rent on the back end in order to satisfy those that just gave you the grant money. Our cost was 5%, so about $50,000 (roughly) was what we put out. In order to cover our cost of building in 3 years, we could charge around $150 per month. Realize that there is ongoing preventative maintenance and utility costs in this as well. Unfortunately, big daddy that just gave you the money doesn't view it this way. They want you to charge a rental rate that sees you recoup the $1,000,000 in a reasonable amount of time. So what do you do? Charge the $150 because it is a good representation of the average in the area or charge hundreds of dollars in an effort to get close to the million dollar mark and get few takers?
There is also plenty of planning that goes into building a hangar. You don't just wake up one morning and realize you want to build one and then do it. At least in our area, these structures need to be represented and planned out on your layout plan. Not on the plan, probably not getting grant money to do it. Also, there's only so much grant money to go around. Small airports get $150,000 a year that they can use toward building a hangar, as long as all your other stuff is in order (trees, land, safety, etc...).
So why don't airports just let private individuals build them with a ground lease? As someone that has been stuck with a few of these deals recently, let me tell you, it's not desirable. Tenants who are not actually your own can become a major PITA. Also, the FAA doesn't really like to see the very long term leases that used to exist out there anymore. With 10 years being the average now, it's hard for many to justify building a set of hangars and then charging a reasonable rate to recoup their expense over that 10 years.
There are lots of things to be considered other than waiting lists out there. Some airports are fortunate and can do these things. We recently got back in a spot where we can move forward with these projects. As I mentioned earlier, we just completed a 10 unit structure and are in the middle of building a 80x80 storage hangar as well. We'd like to keep building since I've still got a waiting list of around 30 people, but funds are short and construction keeps getting more expensive as the economy picks back up. It's a balancing act.