John,
I don't know Pegasus airlines at all but have used Turkish airlines and they are very good, cheap and reliablee

have you tried asking our flight experts yo will find them on the flight and airport forum

wizard

I think Kiss flights do them.

Steve

jcbrum try these sites
http://www.letsgoistanbul.com/domesticflight.htm
http://www.sunexpress.de/about-us/sunny-news/sunexpress-starts-to-fly-from-und-304-stanbul-sabiha-goekcen_100296_102361.html
http://www.airninja.com/discountairlines/fromIstanbulTurkey/toDalamanTurkey.htm

Also on tip of advise....if you are paying by credit card it will ask you for the type of credit card being used...for a previous guest of mine I phoned to atlas jet because they were having troubles...I was told over the phone for all foreign cards ( non turkish ) to use or click the selection for the BONUS card.....you may need this advise later...and I hope it helps and maybe this is the same problem with Pegasos..give it a try or try another credit card..

more info here at this link

http://www.tripadvisor.com/ShowTopic-g293974-i368-k1277470-Trying_to_book_ticket_on_Atlasjet-Istanbul.html

http://www.onurair.com.tr/
http://www.thy.com/
http://www.atlasjet.com/
http://www.flypgs.com/
http://www.sunexpress.de/english/announcement_100126_0.html

Turkish airlines has the easiest web site to use..IMO..but try the others as well

salford_steve wrote:

I think Kiss flights do them.

They are agents or Pegasus in the UK, but only offer flights between the UK and Turkey.

Darren