This is a slightly different scenario, as United's long-term UAX strategy includes more 70/76-seaters than are currently on order, but they can't exceed the 2016 cap of 255 frames unless a new small narrowbody is brought on property (additional 737/A32X do not count). So, it is assured that United will be adding a new type, but the question is which. The two realistic options are the E-Jets or C-Series.

The original E190 is widely considered to be underwhelming from an operational standpoint, even though it hits a sweet spot in terms of capacity/range/comfort. For the right price it is an intriguing possibility.

On paper, the best airplane in the category is going to be the Bombardier C-Series, but there are some questions about the P&W Geared Turbofan engine and whether Bombardier can deliver the airplanes up to spec. After the 787, UA is proceeding very carefully with new aircraft/engine technology.

The E2 brings the same engine as the CS, and is considered a 'safer' alternative as it is based on the proven E-Jets. However, projections are that the C-Series will best the E2 operating costs, so it remains to be seen which direction UA will go.