Your local independent travel agent often knows the best flight deals. Here are a few links to find flights on the Internet to Dalaman which is the nearest airport to Marmaris:

http://www.easyjet.com/en/book/index.asp
http://book.flythomascook.com/skylights/cgi-bin/skylights.cgi
http://www.monarch.co.uk/
http://www.jet2.com/
http://www.thy.com/
http://www.kthy.net/

We can help with transfers from Dalaman or any other nearby airport (Izmir, Bodrum) where you'll be met at the arrival gate and driven in air-conditioned cars.
We can arrange car hire. Ask us for special one-week or two-week rates, which can include 24-hour pick-up and return at Dalaman Airport. Long term car rentals are negotiable.