<font face="Verdana, Arial, Helvetica, sans-serif" size="2">Originally posted by lunarbrian:
I apologize if this thread is repetitive-I did a search and didn't find anything.
I am planning a long trip using miles to Nairobi. One itinerary will be SFO-LHR and back, probably on United. Second itinerary will be LHR-Nairobi and back on BA.The trip is about 17 days so I am concerned that if I book the outbound flight as early as possible, the airlines won't allow a 17 day hold until I can book the return flight. Any strategies on how to make this work? Thanks in advance.</font>
The details may be airline specific, so you may want to ask both in the BA and UA forums.
With BA, I can tell you that it's not as simple as flights 17 days later becoming available 17 days later. BA award availability goes in and out and up and down in magical (black magic?

) ways, and seats can be there and disappear and be there again and disappear again many times, perhaps sometimes even within a span of 17 days (but certainly over a few months MANY MANY MANY months out when hardly any tickets have actually been booked yet).
But you did say this is with miles. Again, I can only tell you about BA, but at BA, as long as the flight is on BA metal (do NOT use miles for BA partner flights unless your flight dates are SET IN STONE!), you can make changes after the initial booking (as long as the seats are available for the same awards on the new dates/times you want), with either no or a fairly small (compared to the "cost" of the flight) change fee. You'll want to (a) verify exactly how this works at BA, and (b) find out how it works at UA, because if one airline has a more flexible change policy it may make sense to book something/anything early and then change it to something better as the schedule opens up (or again, as award seats reappear after disappearing

).
(I presume you don't have enough BA miles to make it all BA, since it'd presumably be easier trying to keep it all BA if you did.)