NOTE: If you downloaded and installed the 747-400/8 base packs after 21AUG15 20:00Z you don't need this hot fix, check your aircraft.cfg files they should have HotFix1 written at the top.
Due to a mistake in both the FS9 and FSX FDE's FAIB's Boeing 747-400/8 will tend to cruise at a slower speed and deploy a small amount of flaps.
In order to fix the problem please do the following steps:
1. Go and re download the 747-400/8 base packs, make sure to clear your browser cache so as to not get the older files you previously downloaded, you can check the date of the aircraft.cfg files in the base packs, they should be dated 17AUG15 for FS9 and 21AUG15 for FSX.
2. For your version of the simulator (FS9 or FSX) copy the corresponding .air files and overwrite the old versions.
Don't mix the FS9 and FSX .air files, FSX version size is 7kb while FS9 version size is 9kb.
3. Open your existing aircraft.cfg files for every 747-400/8 variant you have and search for the line: max_indicated_speed
4. Change the max_indicated_speed = 250.0 to max_indicated_speed = 278.0
5. Save the file!
Your 747-400/8 should now cruise properly without flaps.