A very rural French protest?

On our way back to the Gite on Saturday we passed this convoy of tractors and people marching.

The tractors all had tree branches attached to their cabs and were beeping their horns.

We saw some signs with an aeroplane with a cross through it, so maybe the protest was against an airport, but the nearest airfield is a tiny place so not quite sure what all the commotion was and why the tractors all had trees on them.

Very French!