The airplanes in Vaikuntha isn't exactly like the airplanes here, but it is something like the swan while flying, in shape, with a throne on the back, bedecked all over with golden filigree works, and looking very brilliant. It isn't a bird flying, but the shape of the plane is like the swan bird flying.
The demons could assume any gigantic shape they liked. They can play jugglery; they are not ordinary human beings. You must know that a person with whom God had to fight is not an ordinary person. He could play almost equally with the Lord, but nobody can excel the Lord. Therefore, he was killed. To expand and to reduce the body is sometimes performed by a successful yogi.
Yes, Varaha is very beautiful. Generally, the Boar picture is depicted as half human, and half boar, but in Bhagavatam it is stated that full boar. You can make the first 2 legs as 2 hands, and the rear legs and legs, and make it as beautiful as possible.