1) Do the airlines that operate the Beech 1900's put F/A's on the flights?
In the United States,
FAR Part 121 flights of 20 passengers or more require a flight attendant. The 19 passenger Beech 1900 and Metroliner aircraft get around this. Both aircraft have small cabins and there is no galley, F/A seat, or lavatory.
2) Out of all the routes would Economy Plus be profitable (as in the first 2-3 rows have extra legroom, but to sit there passengers would pay maybe $20.00 extra?)
When Beechcraft (1900) and Fairchild (Metroliner) manufactured these airplanes, they knew that they could get around the F/A requirement if they had 19 seats, so they designed the cabin so that there would not be a space for the F/A's, or for "Economy Plus", the seats are relatively small and narrow, and the flights are priced reasonably, some aren't though, so that the average business commuter passenger could afford to commute often.
3) How loud is it inside of the aircraft?
The 1900 is powered by a more powerful version of the
PT-6 engine that powers all King Air's. I believe there is some more soundproofing on the 1900's, but the King Air 200 and E-90's that I've flown, even without an
ANR headset, the cabin is extremely quite compared to that of a piston engine.