So I will be making a third trip to a small mexican city that is served by one daily ERJ flight. Doing business in Mexico is not something you can set your watch by. My last two trips I had the need to change flights and could not on two occasions due to oversold situations. So my question is. Can I buy a one way ticket to this city and two one way tickets (refundable on different days) to return to houston? If I use the earlier ticket I refund the later. If I need the later ticket I refund the earlier before flight time. I know this is lost revenue potential for CO, but I don't see where I have a choice due to the seemingly constant oversold situation on this route. I do not wish to stay in this town any longer than needed so simply buying the latest possible day and staying extra when I do not need to is not an option.

There is nothing wrong with buying multiple seats on different flights. This is why CO is willing to oversell - they expect some folks to cancel.

CO has systems in place that will prevent you from booking multiple seats on the same flight (search for "super dupe snoop"), but you can absolutely have multiple reservations between the same cities. I did it recently with two different returns from SEA-EWR while I was decided between the late afternoon flight and the redeye.

I have heard talk of if you book back to back flights on the same day being cnx. IE BOS-EWR 630am and next flight at say 730am. I have booked dup's TONS of times, with no problem.