In the latest earning call, United announced that they are bringing Economy Plus and First Class to Bombardier Q400 planes.
While one may wonder why they are putting first class on a prop plane, it does actually make sense. Currently, the Q400s fly for Continental and a large number of them are based at Newark. As many folks know Newark is known for it's ATC delays, along with it's other NYC area counterparts. The regional carriers are generally the first to be impacted during any sort of ATC actions and putting first class makes sense as a lot of these routes are also high-revenue. By putting a premium product on these planes also helps make the transition easier for other high-revenue routes such as Newark - Washington Reagen, which will soon see the return of Q400s.