U.S. airlines are expected to carry more passengers this spring than they have in seven years, Washington-based trade group Airlines for America said on Wednesday.

The group estimates that about 134.8 million passengers will travel on U.S. airlines during March and April, up almost two percent compared to the same time last year.

U.S. carriers are increasing the number of seats available for booking by 3 percent to accommodate the demand, the group said in a news release.

Airlines for America "attributes the increase in spring air travel to rising U.S. employment and personal incomes, an improving economy, the highest consumer sentiment in a decade and the continued affordability of air travel," the group's Chief Economist John Heimlich said in the release.