United Airlines has raised its fee for the first checked bag from $25 to $30 for domestic flights and flights to Canada, Mexico, Central America and the Caribbean. This matches the increase JetBlue announced earlier in the week. United also is raising the fee for a second bag from $35 to $40 for flights within the U.S., Caribbean and Central America and from $35 to $50 for flights between Canada and the U.S., Mexico, Caribbean and Central America. The new fees apply to tickets bought or voluntarily reissued after Aug. 31. Complimentary baggage allowances for MileagePlus Premier members and MileagePlus credit card holders continue to apply.