You should check the amperage rating of the power strip and the amperage drawn by the window ac before plugging it into a power strip.
If your window ac is a 5,000 BTU window ac then it's most likely safe to plug it into the power strip assuming you have no other large amperage drawing things on the power strip.
I run a window ac that is 5,000 BTU in my home office where I'm sitting at the computer right now and it has been fine for going on 3 years now.
All I have plugged into it besides the window ac is the desktop computer.
If the window ac is larger than 5,000 BTU then I would not recommend plugging it into a power strip.
If possible it's best to have the window ac "especially if it's larger than 5,000 BTU" on it's own dedicated outlet and circuit.