The phrase "short runway" refers to a landing strip at an airport that is not very long in length. It means that airplanes have less space to land and take off compared to longer runways. Full definition
Some aircraft with lower temperature tolerances will far worse than others, and certain airports — those with shorter runways, in hotter parts of the world or at higher elevations, where the air is already thinner — will suffer more. (sciencedaily.com)
But the 18,000 - foot mountains surrounding Paro, plus its unusually short runway, make getting there a scary proposition: Takeoffs and landings are among the world's most difficult, and very few pilots are qualified to land there, according to the Daily Mail. (businessinsider.com)
After all, entrepreneurs tend to have very short runways. (inc.com)