I flew Yemenia airlines domestic flight from Sana'a to Seiyun round trip. It was US$145. I booked the air ticket through a traverl agent before my arrival. There is daily flight, so there should have no problem during low season.
The 737 aircraft looks quite new. Inside the aircraft, the monitors even has 3D flight path, which was the first time I have ever seen so far. Even Emirates, Singapore airlines, Cathay Pacific, Air France, Continental airlines which I have flown in the last 6 months do not have. See more pics for the monitor.
Form Seiyun, you can take shared taxi for YR100 (30 mins) to Shibam. The taxi will wait for 5 pax beofre it starts off. From shibam, the atxi with the same fare for return. But the later you come back, i.e. the darker the sky is, the most difficult for you to get shared taxi and you may end up chartting a taxi for YR500-1,000 (May 2008). So do take note.
See pic for taxi condition.
The bus to Sayun from Salalah leaves a couple of times per week.
The bus I took left Salalah on Monday morning at 6.00 and cost 10 Omani Rials. The Omani border crossing took a couple of hours (10.30 to 12.30) and the Yemeni border took a further half hour.We arrived in Salalah at 20.30. I think it is cheaper if you buy a return ticket from Salalah.
I left Sayun for the return trip to Salalah on a Tuesday at 16.30 (cost 4,880 Yemeni Rials).
By far the most interesting scenery was leaving Salalah as the bus climbs out of town, and then again about an hour short of Sayun as the bus decends into an amazing Wadi just before sunset. The rest of the scenery is flat desert, and a hell of a lot of it !!