Airlines these days are charging all kinds of extra fees in order to make extra money. We're not just talking fuel surcharges here, which go up and down and are a part of your fare. These are all the other things, many of which are hidden on airline web sites and which you only learn about when it's too late. So in the interest of full disclosure, we're going to start doing what the airlines should have done long ago: put all the fees in one place, airline by airline, so you'll know what you're getting into.

We'll start with American Airlines. Here's what you may be charged for domestic flights:

Checked baggage (each piece, each way)

First checked bag: $15

Second bag: $25 (except for first, business, full fare passengers and upper level frequent flyer members)

more info

Excess bags: $100 per piece for the 3rd, 4th and 5th checked bags; $200 per piece for the 6th checked bag and any additional pieces

Overweight bags: Checked baggage weighing over 50 lbs/23 kgs but not more than 70 lbs/32 kgs will be charged at the rate of $50 per piece.

Checked baggage weighing over 70lbs/32 kgs but not more than 100 lbs/45 kgs will be charged at the rate of $100 per piece.

Oversized bags: $100

Booking tickets

Booking online: no charge

Booking by phone: $15       

Booking in person: $20

Changing a reservation not made on AA.com or with an AA representative: $15

Children

Lap children: 10% of the adult fare on international fares

Unaccompanied minors:

$60
$100 each way
More info

Frequent flyer tickets

Cashing in miles last minute: Travel ticketed 20 to 7 days  prior to departure $50

Travel ticketed 6 days to 2 hours prior to departure: $100
(When multiple awards are claimed at the same time, each additional award is subject to a fee of $25)

Tickets issued in person: $20

Redepositing miles if not used: $100

Changing frequent flyer tickets: $100 (MileSAAver Award tickets for which the only confirmed change is to the date and/or time will not incur the change fee)
More info

Pets
In cabin:

$80
$100 each way

As cargo: $100 each way
More info

Seating
Advance seat selection: none

Exit row and other “premium” seats: none

Ticket changes (non-refundable tickets, domestic fares)

Changing travel dates after purchase:

$100
$150; For international fares: $150-$300
Fare drop refund (fee charged for re-issuing ticket if a fare goes down between the time you buy and the time you fly): $100
More info

Same day confirmed standby on an earlier or later flight: $25
More info