Director of, among many others, Stripes and Ghostbusters. He directed and/or produced quite a few very funny films.
I still consider Ghostbusters to be a classic. Ivan gave us a lot of laughs.
Came in to report this. He had a stellar resume of classics under his belt.
If you had to pick one director that defined the 80s, Reitman is the only one that could have beat John Hughes.
Reitman had a sequel to Twins in pre-production titled Triplets. Arnold Schwarzeneggar and Danny DeVito reprise their charaters, and this time around discover they have a sibling (who may or may not be Eddie Murphy.)
I’m not sure it would be a great loss if it gets scrapped now. R.I.P. Mr. Reitman. Dave was a great flick
He lived long enough to see his Son complete the new Ghostbusters: Afterlife. Jason said in 2021 interviews that his dad was among the first to read the finished script. He also visited the set during filming.
Ivan directed many of my favorite comedies. Animal House and Ghostbusters are extremely funny.
Some trivia, Reitman directed Rabid, with Marilyn Chambers in a rare non adult starring role. It’s actually pretty good low budget horror.
RIP
I’m afraid you’re off here. Rabid was one of David Cronenberg’s defining “erotic horror” films. Reitman was one of its executive producers.
Oh, I had forgotten that Ivan didn’t direct that project. Rabid is a good film.
I looked at IMDB and see he was producer on Animal House. It’s hard to remember which films people produce and which they direct. Sometimes it’s both. 
A very sad day, here’s to not crossing the streams in the afterlife.
Ivan was a local boy, attending high school less than 1km from where I am sitting now.