There’s an intense fight in Congress over Southwest Airlines and its home airport of “Love Field” in Dallas, and Iowa Senator Tom Harkin has entered the fray. A 26-year-old federal law restricts the length of flights into and out of Love Field. At the time, the restriction was intended to help the then-new Dallas-Fort Worth Airport. But others say it has restricted commercial travel, and prevented Southwest from flying to some destinations. Harkin has proposed prohibiting all commercial flights to and from Love Field in Dallas, and switch all commercial traffic to Dallas-Fort Worth Airport.Harkin says a bill introduced by another senator would reduce increase flights in other areas of the country, while reducing flights into and out of Iowa airports. “That’s why I’m involved in this fight,” Harkin says. “I’m going to fight for my constituents, too.” Powerful Texas lawmakers, though, oppose any changes in the federal rules on flights into and out of the two airfields in Dallas, and its unlikely any changes will be made.