I am assuming they are raptors. I appear to live right on the boundary of 2 pairs home range. They chase each other off if one pair is caught on the wrong side of the border, they spend most of their time using the thermals rather than flapping their wings. I haven't seen them up close, usually about 3 or 400 feet in the air. They are big, about 3 times bigger than the local crows. They have large wedge tail. Their call is similar to a squeaky wolf whistle.

Has anyone any ideas what they maybe?

Oh gosh! You are living right in the middle of a war zone? Be very carefull then for white sticky missiles!

Sorry, doing my account. Brings you in veeeeeeeeeeeeeeeeeeeeeeeeeeery strange mood :D

mosha, thai raptor group (a thai raptor watching society) has a gallery on their site that might have pics of the birds you are seeing:

thai raptor gallery

Its mostly in thai but once you figure it out you could post the name here

From the nearest picture to it I saw, I got this from it'e Thai name and ran it through Thai2English.com

นก อินทรี ดำ ตัว เต็ม วัย

nók in-see dam dtua dtem wai

Another search I found described more or less how I saw these birds flying. The description seemed to match Black Eagles. They do seem to fly around just above the tree tops. I'll try to get a photo, or a short video as that will have their call on.

Tried and googled นก อินทรี ดำ ตัว เต็ม วัย and got

Bonelli's Eagle

Unlikely that they are Bonelli's as they have only rarely been recorded from Thailand.