Hi - we purchased tickets on United for a flight from San Fran to NY and then Alaska Airlines from Washington to LA. I don't think the fare included any amount for checked luggage. We'll probably each be carrying suitcases up to the 23kg (50lb) amount plus a carry on. Can you please advise if we will be able to pay to check in luggage at the airport when checking in on the day of travel and if we do what this will generally cost? I looked on the United website and it appears that it is $25 per 23kg bag and $35 for any second bag per person - is this right and is that the amount you pay if you pay at check in at the airport?? Someone has told me that when they tried to check in a suitcase at the airport in the US for an internal flight the airline tried to charge them $50 per kg (and this wasn't per kg OVER 23kg it was $50 PER KG) because they hadn't paid for checked luggage when they made their booking.
When booking on line in Australia "budget" airlines ask if you want to check in bags when you are making your booking and this will cost say $16, but if you haven't paid for check in luggage and your bag is found to be over a carry-on weight when you rock up at the airport it can cost up to $20 more for up to 23kg.
But we weren't asked about checked in luggage when we were making our on line booking with Expedia and now I'm worried.
Can anyone help please?

United's website seems clear to me. No penalty if you don't pay the checked luggage fees at time of booking. The website specifically says you can pay the fees when you do online check-in for your flight or when you arrive at the airport. There are significant additional fees for overweight luggage, so pay attention to that part of their policies.

http://www.united.com/CMS/en-US/trav...aggageFAQ.aspx

http://www.united.com/web/en-US/cont...0BF6D5F1693CC5

I'm not as familiar with Alaska Airlines, but its policies seem to be more or less the same as the United policies, although their fees and overweight penalties are lower.

http://www.alaskaair.com/content/tra...ges-allowances

FYI, neither United nor Alaska are considered budget airlines. You should ask the "someone" who told you of their experience which airline they were using.

US-based airlines would not charge a fee per kg. If anything, it would be per pound (and a fee of $22.73 per pound, the equivalent of $50/kg, sounds highly suspect; $50/lb sounds even more suspect).

You will pay a FLAT FEE for each bag under a certain weight. If the bag is overweight you'll pay additional. Bag fees in the US are based on the "piece" system, not the weight system as they are in Europe.

The United and Alaska Airlines websites are very clear about these charges and yes you can pay at check-in..in fact you will HAVE to pay at check-in or you won't be checking any bags at all.

Yes, you can pay when you check-in online or you can check in online and then tick the option to pay at the airport.

Are either of these flights within 24 hours of you arriving from Australia or flying to Australia? I ask only because most airlines will waive the baggage fees if you have just arrived say from Sydney into San Fran, and are flying out within 24 hours, United will allow you to check your bags in for free. But you can only do this at the airport and with a check-in person, not an automated check-in machine. Same on the way home, if you are flying into LA to catch a flight back to Oz within 24 hours of arriving, Alaska Air will allow free baggage.

I do this all the time and most recently in Feb this year.