American Airlines tweaked its schedule from Pittsburgh International Airport, adding a daily trip apiece to eastern and western destinations.

Since September, nonstop service to Reagan Washington National Airport in Washington, D.C. has been operating five times a day, up from four.

In November, nonstop service to Phoenix is scheduled to receive a second daily roundtrip flight. The carrier had most recently operated twice-daily service to Phoenix in April.

While American is the only carrier to fly into Reagan from PIT, United offers nonstop service to Washington Dulles. Southwest also offers daily nonstop service to Phoenix.

An American Airlines official said the changes were seasonal adjustments.

American and Southwest are PIT’s two largest carriers. Year-to-date through August, Southwest carried about 25 percent of passenger traffic while American carried about 23 percent. American leads in the number of daily flights.

In addition, American’s daily roundtrip service to New York-JFK, which had been scheduled to increase from one to four in November, is now scheduled to start four times daily starting Jan. 7. Officials noted schedules are subject to change.

American also offers nonstop service to New York-La Guardia. Other carriers offering nonstop service to the New York area include Delta to JFK and La Guardia and United to Newark.