You asked whether our birds are flighted.
All three of our birds – African Grey, Dusky Pionus, Cockatiel – are fully flighted.
We have a lot of large windows in our apartment but so far we have not had a problem.
They all have their favorite routes and pretty much stick to them.
The only time we have clipped our bird’s wings is when we were traveling internationally and they had to go through the health and customs inspections at the airports.