The Microsoft Flight Simulator promises to be very large, but pilots will inevitably want more. It will launch with every airport in the world and lots of planes, from huge international airports to tiny landing strips in the middle of a field, but there are still gaps. That's where modders and add-on developers come in.

For example, you may notice that most of these airports are not detailed and hand-crafted and are missing your favorite aircraft. Creators are already trying to fill such gaps. Orbx, for example, has announced that it will develop an add-on for the sim, similar to the add-on for Microsoft Flight Simulator X. It will be the first in the series that modders will be able to sell directly to players in the game.

"The third-party creator community is incredibly vibrant and has entertained Simmers with their creativity for years," said Simulator X CEO and founder, David H. Harris. "We recognize that third-party creations are an important part of broadening and deepening the flight simulation experience, and we are pleased to announce our Marketplace Partner Program, which will allow approved partners to sell their content in a built-in marketplace We are pleased to announce the Marketplace Partner Program, which will allow approved partners to sell their content in the built-in marketplace.

Modders must become a partner before they can begin selling their products, but participation is free and there is only an approval process. In the marketplace, you can check the performance and revenue of your add-ons, and you will be paid automatically.

Prices are set by the modder, and becoming a partner does not prevent you from selling on your own site or elsewhere. Says Asobo, "We try to approve as many partners as possible."

There is also good news for alpha testers: the closed beta for Microsoft Flight Simulator will begin on July 30, but alpha testers can get in earlier. They are the lucky ones. If you didn't get a chance to play the closed beta, don't wait too long to do so; Microsoft Flight Simulator will be available on August 18.