"Encouraged by the increasing passenger and cargo loads, and fueled by increased oil exploration and production, Sonangol wanted to expand the scope of the Houston Express concept and purchased two ex-ANA B-747-400 aircraft towards that end."
And
"We recently learned, however, that SonAir selected Atlas Air, and we were informed that one of the key reasons for this decision was Atlas Air’s willingness to operate the program with integrated cockpit and cabin crews. As this program is operated under the DOT’s private charter rules, SonAir will eventually need to file for DOT approval."
Disclaimer: Copy paste of a copy paste from another board. Cannot verify origins but said to be from World.