Thanks to a startup called Sojern, customers of some of the nation’s biggest airlines will soon see ads on the boarding passes that they print at home.

Is this just another way for consumers to get spammed? Joshua Goldman, a venture partner at Norwest Venture Partners (one of Sojern’s investors), says it’s not, because the boarding pass allows the ads to be carefully targeted, so it should be relevant and useful. For example, your boarding pass will now include things like event and dining listings, weather information and coupons for local businesses. You can click on the ads when you check-in on the airline’s Web site, but they’ll also be included in the printed document that you carry around at the airport. And yes, there will be an option to print the boarding pass without ads, too.

Delta Airlines is launching the service today, starting with passengers flying to Las Vegas (there are some pretty obvious opportunities for travel-targeted advertising), and Continental Airlines, Northwest Airlines, United Airlines and US Airways have also agreed to add Sojern ads to their boarding passes later this year. [Update: American Airlines is one of the partners, too.]

Omaha-based Sojern has raised a $16 million first round of funding from Norwest and Trident Capital, bringing its total financing to $20 million. It’s no secret that the nation’s airlines have had a tough time recently, but Goldman says that didn’t deter Norwest from the investment — in fact, it makes Sojern looks even better, since airlines are looking for new revenue opportunities that don’t require any extra spending.

Sojern also announced the appointment of Jeffrey Katz to its board. Goldman notes that as the founding chief executive of Orbitz, Katz has plenty of experience working with different airlines.

You can watch a demo of the Sojern boarding pass here.