Domestic: cheapest available Y fare. VP and above can fly J or F if over 4 hours (per segment, not overall trip time). If the VP is traveling on the same flight with a lower-ranked employee, that employee is also eligible for J/F.

Int'l: If the flight is under 4 hours, must be in Y,
otherwise biz. This rule applies to all employees. Technically, if you have a connection to a gateway (e.g., RDU to DFW), that leg would have to be in Y, even if the next leg (e.g., DFW to ICN) is in a premium cabin. In reality, we typically are booked by the TA into the front on both legs :-)

Lounge membership: not provided by the company. No worries, as I use my personal Amex Plat for this.

Preferred carriers: AA and DL.

Overall, a pretty generous travel policy, IMO.