29. What’s got 4 engines and flies daily between LAS and LAX?
I'm wondering if this was the swan song for the ex-PSA BAe 146s in USAir livery ... I rode N175US on this route in 1988
"Wondering" would suggest that you've still not settled upon a set answer just yet. As such, it would only be polite to let you wonder on until you feel more certain as to your choice. Good luck, J!
Please replace "wondering if" with "willing to speculate that" 
An excellent choice of words there,
J, and as such, yes - you are indeed correct! US Air BAe-146 is the right answer!
23. Despite its name, Indianapolis based Lake Central Airlines flies to only three cities that are located on lakes – albeit Great Lakes at that. Identify those three cities.
Let's go with four -- the three on Great Lakes being Chicago (Lake Michigan), Cleveland (Lake Erie), and Buffalo (also Lake Erie); while Detroit is technically on the Detroit River between Lake Huron and Lake Erie, a large part of the metro area actually adjoins Lake St Clair
Sounds good to me,
J. Lake St. Clair definitely counts. And - call it a bonus question if you like - I've found one more city, also situated on a great lake. Care to have a guess which one it is?
Two possibilities, both on Lake Erie, come to mind: Erie PA and Toledo OH
Man oh man! When it comes to cities on lakes, You Da Man!!! Good call! ^^