Image Source: @southwestair on Instagram

In the past, it was called the Southwest Effect.

Just about any time Southwest entered a market, airfares to and from that market dropped substantially.

Well, that Southwest Effect has now been extended to JetBlue, WOW, and the Norwegian Air Shuttle.

In some cases, it happens even if those carriers aren’t competing with other airlines on the same route.

Take the New York to Boston shuttle, for example.

It’s a route long dominated by Delta and American.

Coach airfares on this route were routinely high—$800 for a round trip on flights that lasted about 38 minutes in the air.

Enter JetBlue, and we’re seeing shuttle flights for $67.

The Norwegian Air Shuttle is now flying between Hartford, Connecticut and Scotland.

Fares have been as low as $70.

It doesn’t even have competition on that route.

Some of these are introductory airfares.

In many cases, as other airlines match the low fares, the early fares will stay low longer than normal.

For more information about air travel, check out:

• What the Travel Ban Means for Americans
• How Domestic Airline Performance Improved in 2016
• Airlines Introduce Lie-Flat Seats in Business Class

Keep reading for more travel tips.