scenario: a Saturday Air operation comprised of Bid Air Drivers. These are mostly part time air drivers (3 hour daily guarantee) whose schedule is Tuesday through Saturday. Another sector is a few Bid Air Drivers who are scheduled Monday through Friday and come in on Saturday as an additional earning opportunity. Yet another group is a section of inside part time employees who come in on Saturday as an additional earning opportunity. And finally, another sector of full time ground drivers. These guys come in on Saturday also as an additional earning opportunity. They are entitled to 8 hours. They will almost always take time worked instead of bumping a part timer. The problem we are having is figuring out who comes first when. It comes to additional earning. (Going to the airport at 5am pick up the work and staying late to do pick ups.) I was under the impression seniority rules. The union is telling us because it's a certain Bid Air Drivers "bid day" this particular air driver with 4 years of seniority goes to the airport in the morning and stays late to do pick ups, puts in a 12 hour day. Does a part time bid air driver working on his bid day with 4 years trump another part time air driver with 14 years working on his day off as an additional earning opportunity or an inside part timer with 15 years working a Saturday as an additional earning opportunity? Also, does the issue of whose at top rate as an Air Driver factor into this mess? I look forward to your responses.