Dog has become scared of planes, any ideas of how to calm?

[CatastropheKate]

Dog is 5 and never used to have a problem with planes until he was trampled by sheep when a military jet startled them. Now he gets scared and distressed when he hears them (jets, not sheep!) which to be honest is only every couple of weeks or so, but it seems to be getting worse over time, not better.

Anyone have any ideas of how to calm him?

Should've added that he has no problem with regular small planes, just the loud jets.

Obviously you can't really control when he's likely to hear the jets out in the real world so I'd start with a recording (there are lots of videos on YouTube of jet engine sounds) and work on desensitising him to that. You start with it at a very low volume, quiet enough so he's not bothered, and reward him for not reacting. Then very gradually up the volume, always rewarding him for not reacting. If he does react then it's too much and you need to go back to a volume level he was comfortable at.

demonstrates it pretty well.

It might take a while, especially as he'll probably be exposed to the real thing during the process, but it should help.

He's a bright dog, he knows the difference between noise from the laptop and real life - we've already tried it.