Hi flyingkangaroo and welcome to A.net!
is what you need: http://www.projectai.com
Go to the official files section and download the PAI-installer. Now you can download the traffic remover from there, but I advise you to remove your traffic.bgl file as suggested in a thread here (their traffic remover doesn't remove all traffic).
When you're done removing the traffic, either by their uninstaller or deleting the file, download airline and/or cargo packages from the same website (in the official files section again). These are zip files, unzip them and you have your PAI-files. These PAI-files can be installed using the previously downloaded installer.
Good luck and have fun!
[Edited 2004-04-16 22:41:56]