ED DCS World Forums are ablaze with speculation, consternation and perturbation.
If you backed DCS World War II on Kickstarter for USD 65 or more, you were expecting to receive a key to the DCS World P51 either at the completion of the Kickstarter project, or latest October 2013.
Hard to see that there could be any question or confusion. The rewards are laid out on the Kickstarter page:
Those keys, like the project Developer, have gone missing in action according to the DCS ED forum members who note the last time Shevchenko, I., was on the forum was in November 2013.
Fair balance would suggest the dev team has been rather active with regular project updates, though rather quiet on the issue of when Kickstarter backers will get their promised P-51 keys.
If you want to check details for yourself, here is the Kickstarter page which lays out the rewards...