Every major North American airline has now raised its fees for checked bags except Southwest Airlines, which still allows travellers to check two bags at no added cost, and Alaska Airlines, which still charges $25 per bag, the previous industry standard.

American Airlines and Delta Air Lines are the latest carriers to announce increases in baggage fees, following the trend started by Jet Blue last month and quickly matched by United Airlines, Air Canada, and WestJet, the San Francisco Gate reports.

American and Delta raised the fee for a first checked bag from $25 to $30 beginning September 21, and from $35 to $40 for a second checked bag, mirroring the price structure established by Jet Blue in August.

“This is the first time American has changed its domestic checked bag fees since 2010 and follows similar changes made by other airlines,” American Airlines said in a press release.

Industry experts say Alaska Airlines could be the next carrier to raise baggage fees, which have raked in billions of dollars in annual revenues for airlines. Southwest Airlines officials have vowed not to charge passengers for checked bags.

aa.com, delta.com