It's best to be very clear about what your customers gets, what it will cost them (or profit them) and how it is to work with you. Used to be you could choose an airline by:
1) Comfort level
Not so anymore. Rather than keeping it simple and raising price or better capacity planning, it now takes a spreadsheet just to figure out how much it really costs. Here's a list of the hidden charges for US domestic air carriers:
Reservation by phone
Checked bag charge
Getting a good seat
Beverage / Snack
Non-refundable ticket change fee
And it goes on and on. Yet Southwest has the cleanest policies, most things are free and is profitable. Coincidence?
My advice, keep it simple and over-deliver. At the end of the day you will not only be more profitable, but have more return customers who will sing your praises. And tell their friends.