Although we love Norwegian and how they’ve pushed airfares down for international travel, flying shiny new Boeing Dreamliners nonstop from an increasing number of U.S. cities, it should be noted that older airlines such as British Airways, Delta and American aren’t taking the competition lying down and it’s important to compare fees for bags when buying.

The older airlines have carefully priced their airfares to reflect what they offer for free and Norwegian charges for.

First up, Norwegian charges $130 round-trip for a checked bag on long-haul flights.

Hand baggage isn’t charged, however the size on Norwegian’s lowest airfares is limited to 21 x  15.7 by 9 inches and 22 pounds.  British Airways, in contrast, allows cabin luggage to weigh up to 51 lbs and measure 22 x 18 x 10 inches on any economy class airfare. So if a gate agent at Norwegian weighs or measures your bag, and it’s over the limit, into the hold it goes and that will be $130 please.

Meals are extra on Norwegian and while they’re nothing great in any economy cabin they’re free on the older airlines, plus you get free booze on an airline like BA, although drinking while flying is dehydrating so many people don’t drink alcohol anyway.

If you think airlines don’t weigh cabin bags at check in, you’re right some of the time. I was recently caught on an Air Berlin/Alitalia codeshare flight at check in and my bag was subjected to their very stingy weight limit so into the hold it went.

So what I’m seeing, not surprisingly, is that the older airlines price their airfares higher than Norwegian at about $100, as this random Denver to London example shows ($461 round-trip on Norwegian, $562 round-trip on BA).

They’re banking on the fact that sooner or later consumers will get hit with a checked bag fee and think, “Gee, I could have flown on American for the same price and had a meal and a free glass or two of wine as well.”

Also of note: It’s a minor point perhaps, but when comparing flights to London, Norwegian flies into Gatwick which requires a $46 round-trip train ticket to the city whereas you can take the Tube from Heathrow to Central London for far less.  And if you’re an AARP member (really, anyone can join, they don’t ask for your birth certificate) you’ll save $65 off your BA fare.

You can ignore all this perhaps if you’re traveling with a small enough cabin bag that adheres to Norwegian’s limits on its lowest fares. But if you end up checking a bag on Norwegian, consider the final cost.

So while we continue to feature Norwegian’s great airfare deals, this is all food for thought.