The short answer is "If you intentionally pointed the Luxor beam at an aircraft (flying low enough for it to constitute a hazard) you would probably be arrested". The real question is What would they charge you with?, and the FAA regulations aren't where you want to look for that: You need to look in the "United States Code".
18 U.S.C. 39A makes it an offense to aim a laser pointer at an aircraft. It goes on to define "laser pointer" as:
any device designed or used to amplify electromagnetic radiation by stimulated emission that emits a beam designed to be used by the operator as a pointer or highlighter to indicate, mark, or identify a specific position, place, item, or object.
The Luxor beam certainly isn't that, so you're safe there.
Instead you will probably be charged under a creative application of 18 U.S.C. 32(a)(5), which says
Whoever willfully … interferes with or disables, with intent to endanger the safety of any person or with a reckless disregard for the safety of human life, anyone engaged in the authorized operation of such aircraft or any air navigation facility aiding in the navigation of any such aircraft … shall be fined under this title or imprisoned not more than twenty years or both.
While this law was originally conceived to deal with in-person threats (kicking down the cockpit door and clobbering the captain with a frying pan) it would not take a very creative US Attorney to make the argument that shining a 40 billion candela light at an aircraft's cockpit would "interfere with or disable" the flight crew, and shows a "reckless disregard for the safety of human life".
Similarly it would not take much creativity to argue that swinging such a beam around in the sky in an area where it may interfere with aircraft operations would also show a "reckless disregard for the safety of human life", unless you took the time to file an appropriate hazard NOTAM.
Note that in my initial statement I said that you would be charged if the aircraft were flying "low enough for it to constitute a hazard" -- as has been pointed out non-coherent light source intensity falls off according to the inverse square law, and with sufficient altitude the Luxor beam is just a bright spot on the ground and doesn't have anywhere near the effects of laser illumination.
The Luxor's beam was in fact part of a study on the effect of lasers and high intensity lights in relation to air traffic safety. That section of this report (and indeed the entire thing) makes for interesting reading.