>>1170758That's generally still a thing in a lot of Europe, and also budget airlines almost never use jet bridges.
I suppose the likes of the B737 and the fact that it can have built in airstairs allows for it and other aircraft can sit close to the ground. Other aircraft like the E Jets and the CSeries are already low to the ground. Plus the likes of the Dash 8 Q400 and the ATR have airstairs as standard, partly thanks to their high wing design.
I think tail engines are a dead concept, and part of it is just because underwing designs are now a lot more flexible these days.
