I would like to recommend a business in Udon. Its called Journey Ticket & Coffee. You can book Air Tickets or just lounge around and have a coffee and listen to their cool music, Jazz & Blues etc. Over the last gew months they have saved me money on travelling to bangkok on Thai Airlines, about 600 baht on the advertised price on their(Thai Airlines) Website. Their Iced Latte are delicious also!
Its run by a lovely young lady. Her name is Napat Wudtipacharat and her family. She speaks Perfect English and Im sure you will have nothing but good things to say, should you wish to check it out for yourself...
Contact details are as follows
15/3 Amper Road
T. Makkang, Muang
Phone Number : 042 246662
Fax Number : 042 328832
E-Mail : email@example.com
Ive attached a few pics also