Second in the Lincoln Rhyme series by Jeffery Deaver...
More re-reading! I think I'm mostly going to do a bit of plot stuff since we all know I like this series already.
As opposed to the movie made from the first book, the personal relationship between Rhyme and Sachs doesn't really get going until near the end of this one. He's really almost sweet about it, he's scared and doesn't want to get hurt again or hurt her.
The case is about a professional killer who's been hired to get rid of some witnesses before they can testify before a grand jury. It has the pilots and all kinds of interesting things with planes.
As is normal for Deaver books, all isn't as it seems! But they're so twisty that even though I've read this before it had been long enough ago and convoluted enough that I didn't remember where the twists were. I almost (but not quite) want to read one of his books a second time right after finishing it to read it knowing what to look for. Who knows, maybe I will at some point.