Search lights used to be a standard of advertising for car dealerships, and most of them rented rather than owning. Some of the older sales personnel can probably clue you in as to where you can rent one. They can probably also tell you if there were any regulations regarding how close to an airport you can use them.
Don't go searching for a cheap searchlight without doing serious research first. Fort Mott, a local state park and national historical site, was gifted with a WW2 era searchlight, which then ended up costing $84,000 and several years to restore to working order.