Here is the snippet on jumpin' Skyway from the ALPA website.
Pilots and dispatchers from FAR Part 121 and 135 air carriers are allowed to ride as an additional crewmember (ACM). If the jumpseater is from an air carrier with which Skyway has a reciprocal agreement, the gate customer service representative can sign the jumpseat authorization form. The captain must sign the jumpseat form for any other jumpseat requests. If the gate agent authorizes the ACM, the ACM must obtain oral approval from the captain before taking a seat. ACM forms should be picked up at the gate area at least 30 minutes before departure. Jumpseaters will be required to show company ID and to sign the authorization form. More than one person may be granted ACM authority on any given aircraft. On airplanes having 19 or fewer seats and no flight deck jumpseat, the ACM, at the captain's discretion, may ride in a passenger seat if a seat is available. Jumpseat travel is a discretionary courtesy, subject to all applicable FARs, company regulations, and the captainâ€™s permission. Travel is on a space-available basis. Each person using the Skyway jumpseat must observe strict professional conduct and wear appropriate attire or full uniform. Sterile cockpit procedures must be observed. Website: www.midwestexpress.com
The information on the ALPA site is not current, at least for skyway. I do not have the information in front of me, but we recently received a supplement to our ops manual and I do not think 135 pilots are allowed. Wish I could provide more information but I do know that the information posted above has changed dozens of times since September and the only thing that alpa has been updating (quite regularly) is what airlines are accepting 121 jumpseaters. Good luck. If you are in MKE trying to get a ride and the gate agent says you are not on the list, ask to speak to the captain. If it is not specifically spelled out that we cant give 135 drivers a ride, I think most of us would welcome you on board. I give everyone a ride, especially since everything has changed making it more difficult to get around. If I had 32 pilots in back it would suit me just fine.