Online travel company Expedia said it reached an agreement with Northwest Airlines and KLM to continue to act as an agent for both airlines and do so without adding surcharges to published airline ticket prices. Terms of the deal were not disclosed. The agreement comes as competition heats up between airlines and online travel players. Both sides have been pleading their cases to travelers, armed with opposing studies and each claiming the other will cost it billions of dollars in service fees for every airline ticket bought. Expedia, based in Bellevue, Wash., said the agreement will not impact its financial results.