united.com now has checkboxes when creating an itinerary that allow one to Search Alternate Airports and Search Flexible Dates.

It appears that the alternate results appear - at least initially - only when searching by price. However, in experimenting with the features, the results have so far only indicated "not available" (for both alternate airports and alternate dates).

Like everything on united.com, perhaps a work in progress?


Update: I was able to get alternate dates to work with some domestic routes. It offered complete itineraries offset by a day or two.

Interestingly enough, I also tried selecting alternate dates for a SFO-SIN itinerary, and the system gave me an alternate dates fare of $298.30. This was the same alternate fare as the SFO-JFK fare I had priced just prior, though. Darn.