Will a steel boomerang stay constantlyin the air if a magnet is placed in the middle of its travelling path?

Answer 1

No, because the magnetic flux is not uniform over the flight path.

Answer 2

Lets take this question apart
Will a steel boomerang stay constantly in the air if a magnet is placed in the middle of its traveling path?
Steel Boomerang - Some Stainless steels are non magnetic - Or you could build your boomerang out of Samarium Cobalt or Nebidium (spelling?) for a stronger magnetic attraction.
Stay constantly - constantly indicates forever. To long a time to consider all the problems to be encountered during forever, so no, not constantly.
In the air - Air is a collection of gases that oppose motion Thus the engineering field of Aerodynamics, A boomerang has good aerodynamics but not perfect.
If a magnet - Magnetic strength varies depending upon the material the magnet is made of and the strength of the magnetic field used to magnetize it. For ceramic and rare earth magnets this is done during the cintering process. Magnetic strength falls off by the square of the distance. A slight change in distance is a huge change in the attraction between the magnet and the steel.
Middle of its traveling path. A boomerang does not follow a circular path. Therefore the magnet can not exert the same force all the time.
Any one of these problems causes your answer to be NO.
However strong magnets have shown that they can levitate live objects like spiders by acting on the iron in the spiders body.
Trains and linear motors work with magnets and can move objects so fast that they have been seriously considered for getting material into space.
Magnets are currently in use in the form of gears that do not touch each other which makes the machines they are used in very quiet and long lasting.
Magnets are well worth your interest and the WWW is full of information. Look up Nicoli Tesla the real father of all the electric systems in use today. He made Edison look like a fool.
Rather than a boomerang. Right now you could make a skate board and a large electromagnet say 30 feet by 30 feet and you could fly around over the surface of the magnet and never touch the ground till you fall off. Problem is with only the air holding you back the ride would be so slippery you would need something the size of a surf board or a flying carpet to keep your balance even on your stomach. But think of being the first one to be able to ride a skate board with out wheels through a magnetic field with bumps of strong magnetic field and dips of weak magnetic field that can not be seen. Way cool and currently possible.
It is up to your generation to make it happen. Your parents and their parents and their parents got you this far, what can you do?

Answer 3

If the a strong magnetic moves (very precisely) with the boomerang, it is possible to pull the boomerang anywhere without ever touching it.

However, if you have a stationary magnet that is strong, the boomerang will pass close to it and be pull off course, crashing.