The DFW side asked the court for a rehearing and were denied. They asked the U.S. Supreme Court to review the case, but it refused, not once but twice.

With that matter finally settled once and for all, (or was it?) Southwest focused on its business plan. It began building a small intrastate point to point network. Harlingen was added in 1975, followed by Corpus Christi, Lubbock, Midland - Odessa, El Paso and Austin in 1977.

By 1978 there was good news and bad news for Southwest. The good news was their business plan had proven to be a success and they'd been able to turn a profit for the previous four years.

The bad news was they were running out of places they could go. Since they were an intrastate carrier, they could only offer passenger service within Texas. Based on their business plan, there weren't many other cities in Texas that could support the level of service Southwest would offer.

Help was on the horizon, though. In October, 1978, Congress passed the Airline Deregulation Act. Among it's stated goals:

1. the encouragement of air service at major urban areas through secondary or satellite airports;

2. the avoidance of unreasonable industry concentration which would tend to allow one or more air carriers to unreasonably increase prices, reduce services, or exclude competition; and

3. the encouragement of entry into air transportation markets by new air carriers, the encouragement of entry into additional markets by existing air carriers, and the continued strengthening of small air carriers.

Southwest was no longer restricted to flying within Texas. None of the airlines were restricted. They were free to run their business as thay saw fit without a lot of government red-tape.

In November, 1978, one month after deregulation, American Airlines announced it would move its headquarters from New York to Fort Worth, Texas and open a hub at DFW.

Southwest sought and received permission from the CAB to begin flights to New Orleans from both Dallas Love Field and Houston Hobby.

Interestingly, as part of the Airline Deregulation Act, the CAB - the agency which had ordered the two cities to build a joint airport 14 years earlier - was itself being disbanded. It was an indication that the times were changing. Everywhere except North Texas, that is.

The Fort Worth Star Telegram recounts what happened next:

"Fort Worth and Dallas then asked Congressman Jim Wright, who had opposed deregulation, to do what the federal courts and regulatory agencies would not do: to limit Southwest.

Newspaper articles from the time portray a heated conflict in fall 1979, with Wright repeatedly attaching amendments to bills in the House that would have either closed Love Field to all airline traffic or limited Southwest only to flights serving Texas.

Kelleher lobbied against the measures. A bill backed by Wright that contained restrictive language passed the House, but the Senate refused to go along. Kelleher had allies there, including Sens. Russell Long of Louisiana, Barry Goldwater of Arizona and John Tower of Texas.

A House-Senate conference committee argued for weeks over what to do about Southwest and Love Field.

The legislative stalemate was broken by the proposal to allow Southwest to serve just Texas and the adjoining states of Louisiana, New Mexico, Oklahoma and Arkansas from Love Field. It was a classic compromise: less restrictive than Fort Worth wanted, but more so than Southwest would have liked.

[Southwest's Herb Kelleher] said he agreed to the compromise, but only out of fear that Wright would succeed in imposing far more draconian limits on Southwest. Other members of Congress warned him, Kelleher says, "If you don't take this, you won't get anything."

The Wright Amendment was signed into law on February 15, 1980. The amendment prohibits interstate scheduled passenger service at Love Field, subject to four exceptions:

• unrestricted service using aircraft seating no more than 56 passengers

• ten charter flights per month, and

• the interstate services that existed on November 1, 1979.

It additionally allowed airlines using large jets to operate Love Field flights to or from points in Texas, New Mexico, Oklahoma, Arkansas, and Louisiana ("the Love Field service area") but barred the sale of through transportation between the endpoint of such a Love Field flight and any point outside the Love Field service area.

Thus, if a traveller wished to fly from Love Field to a point outside the Love Field service area, the traveller could transfer at the endpoint of a Love Field flight to another flight going to the point outside the Love Field service area, but the traveller had to buy a separate ticket for each flight and could not check his or her luggage through from Love Field to the final destination.

(Note: Other perimeter-restricted airports like New York's LaGuardia and Washington DC's National don't require separate tickets for each leg and luggage can be checked through to the final destination when traveling to another city outside the perimeter.)

The Wright Amendment does not regulate noise, air quality, safety, or the number of departures out of Love Field. It only regulates which markets can be served based on aircraft type. It's sole purpose was to protect a then-fairly-new DFW Airport from competition.