A way around doing the "come fly with me mission" is to, once in novac go to the motel area. On the first floor of motels there are only two rooms you can go in. The one on the left is Manny Vargas's room. Enter his room and straight ahead is a terminal. The terminal doesnt require any level to hack it. Just enter it and click on the entry and it updates your quest to intercept the great khans, so you dont have to do a favor for many to get the info.

Although you might not be able to get the achievement for the mission "come fly with me", you just saved yourself losing a lot of playtime.

You welcome

Wow! Good job investigating the matter! Very proud of you! Thank you! ^___^* ?

damn wish I knew this before. Its too late for me now, but thanks for the post though.