Could a bird Fly inside a moving Train?

Question

Could a bird Fly inside a moving Train?

Answer 1

What if I am enclosed in a big box which initially has some air. It starts moving at a uniform speed of xKmph. Now suddenly , suppose the box becomes a vaccum. and I jump at the same instant. WHat happens? Will I land at the same place wrt to the box or will I smash the back?

Now what about the same QN when the box is accelerating at 1 mps?