I have 2 questions....first, why can't I open most of the texture bmp files in add on planes? There are usualy 2 or 3 in the directory that will open in paint or whatever, but most of them just show up as white in paint or won't open at all in other programs. Am I missing something here?
Second, what does it take to put a building on a piece of scenery? I live in Gadsden, Alabama and work at International Jets at the airport there. I would love to put our hangars on the scenery there. There is a generic building where our hangars should be. How can this be changed?

Well...question one.......yes as SG just said above...you need the free utility called DXTbmp....which will open those extended bmp files which are used in your a/c texture. It also then allows you to send the file to Photoshop or whatever you use for any changes you want to make and then return the file to DXTbmp for re saving in the correct format.

To add buildings etc......there is the freeware RWY12 Object placer or the much superior but payware Abacus EZ-Scenery which is much easier to use.There is a free demo for this. You'll also need other software to exclude various items which are in the way and to flatten areas which have the wrong altitude......also bits and pieces of files to get them all to talk to each other ...there is also DefArea..which will clear roads ..rivers..and those things like street lamps and pylons which can't be removed by normal exclude methods.....look at these programs ..Google is your best friend and although it's not particularly easy at first it's not difficult........if an old timer like me can sort it then anybody can  

Good luck..........commoner

BTW...this is for FS9....I have no working knowledge of FSx.

For FSX you can use a tool such as Instant Scenery (payware from Flight1) or Whisplacer (free) to place your objects.  If you plan to do more work at your airport then there are three airport design tools for FSX.  AFX from Flight1 (payware), FSX Planner  or Airport Design Editor (both free).  Both FSX Planner and ADE can exclude stock buildings for you and allow you to add new ones.  The next version of ADE will allow the placement of GMax (or FSDS) models directly without having to create a library first.  On the other hand if you just wnat to place a building in one place only you can do this from the design tool (GMax or FSDS)