Mutt,
I agree with you totally. An airline can not base its operations on one destination ONLY.
I am sure that Tair Airways have made a market study & knows what other airlines are doing. Do not forget that they are a charter Airline, so that means they can fly any where on adhoc approvals.
An airline choosing a B747 as their main equipment, means they know that they will fly it at least with a 75% load factor.
Thanks for the information.