Recently there has been a lot of talk of connecting light rail with airports in cities around the country. There seem to be two discussions going on of how to connect to the airport; extending a line out to the airport, and running a line through the airport if its already passing the area.
If the city is building its first light rail line, I'm not sure a move to the airport alone is the best decision for a city to make. While its good to connect the airport to downtown for travelers, they don't make up a big enough share of transit users to justify a first line. The first line, as has been said a lot lately, should be a starter line that will get the highest ridership and connect the most destinations. Extensions can move to the airport and some airports might even be willing to build or pay for that connection such as TIA in Tampa.
In Sacramento, there is a discussion going on as to whether the DNA line should extend all the way to the airport. This is covered with good points by RT Rider. The line is going to go to Nantomas and I don't see a reason why at some point the line shouldn't be extended to the airport. Because so many people go to Sacramento to the state capitol, it would seem to me that there would be a lot more trips than general generated from the airport and would make the city a bit more competitive for jobs and growth.
In Dallas, some locals are upset that the new light rail line didn't get a tunnel to love field which it will pass along its alignment. It is silly for the federal government to base this decision on cost alone (cost effectiveness strikes again) because as Richard Layman discusses, there are much more external benefits that aren't counted in a traditional cost benefit ratio usually touted by the Reason foundation and the anti-transit faction who of course don't use that same measure for roads. But now, Dallas is looking to tax flights to pay for a people mover to connect the airport and light rail station in a subway.
Austin's Mayor and a council member have opened discussions recently to build light rail to the airport. If that line goes through Riverside and up Guadalupe, it would be a good extension, and could possibly spur TOD along Riverside towards the Airport. But perhaps a phase II scheme would be best.
Some here in San Francisco argue that BART to SFO should have never been built but rather Caltrain should have been electrified and a people mover connect the station to the airport. Obviously for me its easier with BART to the airport to get there because instead of a one seat ride I'd have a three seat ride. Obviously I like it, but it benefits me directly.
So what does this mean? Is it important to connect to the airport? Depends on who you ask. Personally, I think that an airport connection by rail is a sign that the city is moving in the right direction. It should be the goal of cities to make it easier for travelers to get places they visit without cars while also making it painless to get to the airport sans traffic jam. But the regional benefits and connections should be taken into account as well.