First fare hike of summer from American, Delta

Some airlines may be fighting back against

reports

of lower domestic fares for summer travel.

Delta

and

American

each raised fares for most domestic routes by $5 each way on Friday. So far, other airlines have not matched, though

Northwest

and

United

have said they are studying Delta's increase before announcing higher fares of their own.

Fare hikes are often rolled back if other airlines fail to match them, but a

Reuters

report suggests increasing fuel costs will make this one different. In the report, JPMorgan analyst Jamie Baker

says, "Given the continued rise in jet kero prices, we ascribe a greater-than-usual probability of competitive matching."

If the $5 increase sticks, it won't apply to

all

domestic routes, particularly ones where Delta and American face competition from low-fare carriers such as

Southwest

. Low-fare airlines generally prefer to initiate their own fare increases rather than match those from other airlines.

Whether this fare hike sticks or not remains to be seen, but you can bet airlines will try raising fares many more times this summer.