Lost in the Fog - Martin L. Shoemaker

Burns Mountain Regional Airport is a quiet little airport in the wilds of the Pacific Northwest. Nothing ever happens there... until The Fog rolls in, bringing with it traffic from other worlds. Then air traffic controller Marla Tucker and the rest of the airport staff go to work, guiding the alien visitors to land for clandestine meetings and mysterious trading. Before The Fog lifts, these strange aircraft will return to their worlds, and Burns Mountain will go back to sleep. 

The Fog Traffic remains a closely guarded secret... until one visitor goes missing, and the Mantis people want him back for an important diplomatic ceremony. Now government agents are taking over the airport, and suspicion falls on Marla and her friends. Marla must decide who she trusts and how far she will go to help a stranger in trouble... while avoiding interdimensional war!

This novella is exactly the sort of science fiction I like, filled with big ideas, interesting characters, and suspenseful action. I'll be publishing a story by Martin L. Shoemaker in an anthology from Rough Edges Press later this year, and after reading that story and this one, I'm going out and hunting up the rest of his work. Great stuff for fans of classic SF.