You need two ladders, an "antigravity board",
a hoop, someone to float, and...
Watch Mr. Blaney perform his trick on The Tonight Show with Johnny Carson. Forward to the one-minute mark if you want to skip Mr. Carson's explanation to the audience that the trick is not accomplished with any camera trickery.
By the way, the trick is not accomplished with any camera trickery.
The Ladder Levitation on Carsons Tonight Show
In this clip, magician David Sandy performs the illusion at the Magic Castle in Hollywood, California. The illusion starts about 3:30.
David Sandy's Blaney Ladder Levitation