US is very strict when to upgrading to the Envoy cabin, heck, they won't even upgrade us employees unless we have the $100 upgrade coupon in hand. To my knowledge OAL employees can't purchase the Envoy upgrade coupon, but you can always double check at a US ticket counter and see if you can purchase one. Or you can be extre nice to the agent working the flight and see if they will upgrade you. It's worth a shot.

Regards,

Chepos