>>We took a flight that was supposed to be 30 mins. after in the opposite direction to pick up one person, a wait of 15 mins and then over an hour back we were over 2 hours. Also factor in then time from airport to the camp, this can often be an hour or more.<<
Welcome to Africa. It's unlikely the air carriers will leave a pax with no way of getting to where they are going, so sometimes this happens. Am sure if it was you, you'd be glad to know you'll not be left behind. And yes... sometimes it can take an hour or longer to reach a particular lodge/camp from the airstrip, but is a game drive. Be glad you don't have to walk!
Likewise, routing can change from day-to-day depending on pax load.
As to flights to Amboseli there are two in the morning (one each Air Kenya and Safarilink) and one in the afternoon (Safarilink).