I loved that airplane scene! And that last bit where Hotch threw JJ a look, got a chuckle out of me.

the rest of the team started talking about how long it takes widowed people to move on. (But weren't Hotch and Haley divorced? He wouldn't be a widower then)

Well, they've never felt 'divorced' to me. They still loved each other till the end. Plus, I think I saw Hotch wearing his ring after the divorce/her death.