Traveling with a Child or a Pet: $10-$100 and up

Toddlers don't take up a seat or add significant weight to the plane, so domestic flights with a lap-riding child is free on airlines such as US Airways and American. But most airlines charge international travelers 10 percent of the published adult fare for a child seated on your lap. Unaccompanied minors have become more expensive, too: Delta recently doubled its rate to $100 and Continental upped its charge to $75 on direct flights and $100 on trips with connections. Even pets have become more costly to travel with: United's carry-on fee for small pets jumped $15, to $100, now matching the rates charged by other legacy airlines, Delta and US Airways. American and Northwest charge $20 less.