My wife and I fly at least once a year with Taca to UIO via SJO from JFK. I recall back in December 2003 they told us to be at the airport 4 HOURS before our 6am flight. We arrived around 3 hours before and there were quite a few people on line already. It has always been generally chaotic at JFK and very slow every time we have flown Taca the past 5 years.
The last time we flew Taca over Memorial Day weekend in 2004 we arrived early, but a co-worker of my wife arrived a little less than 2 hours before the flight and they refused to let her check in and they apparently had no other flights that day to put her on. Her mom and sister who were flying with her had already checked in and that made no difference to Taca. She was in tears, and went home. She later negotiated a partial refund/credit.