Welcome to Flamingo Air: a Cincinnati-based airline that amazingly lets you join the mile-high club (yes, people do have sex in Cincinnati) and claims to be the only such, ahem, service-provider in the US.
Calling them "Flights of Fancy", the basic gist is simple -- the "very discrete" pilot takes two of you up to cruising altitude, and charges a flat rate of $425 per hour (no, they don't discount in case you don't need the other 57 minutes).
This is your trusty vessel: a Piper Cherokee 6. Don't worry, they have a very low accident rate, so you'll be practicing safe sex.
Inside, it's fitted with a special "loveseat" (in the upright position?).
They'll also provide Champagne & chocolates "to aid in the romance".
You even get to dictate the flight path, and pick some Cincinnati landmarks to fly over, in case you want to get to third base while above the Great American Ballpark.