One of my dohai is my closest friend and we meet outside the dojo for different activities. (E.g. I did his wedding ceremony
Some others of the students are also friends and meet outside the dojo.
But besides that, the people usually just come to train. Everyone has his or her own familiy, friends, job ...
We meet to train. Just that.
Even "having a drink in the bar beside the dojo after training" is very seldom.
There are few opportunities like birthday parties or something like that and then it's mostly the elder ones, who know each other for ten or fifteen years, who atcually follow the inivitation.
Sounds harsh maybe, but aikido for most of us is not a "social activity".
Although: When someone needs the others everyone helps. Hard to describe. We are not friends, but know each other very well and often for a long time.
So there are very few social activities besides the training. But nobody misses them because the people are comming to train and not to meet people.
(There are even people who don't want the other students to know their email address.)