Here are my issues regarding the Epic 4G in Airplane Mode. (note: I am rooted on DK28, I normally get locks within 1 to 2 meters now )
1. Turn GPS off. Turn Airplane Mode on. Turn GPS on. GPS will not see or lock onto any satellites.
2. Turn Airplane Mode off. Turn Wifi & 4G off. Turn GPS on while in 3G. Use GPS Status to confirm locks on satellites. Turn Airplane Mode on. Take the Epic for a drive and see how long it lasts. I did this today and lost the locks after 5 miles.
3. Repeat step 2 in an actual airplane. I lost the locks as the plane reached maximum acceleration before take-off (yes, I "snuck a peak at my phone")
I would be most interested to hear from anyone with an Epic that could confirm findings in 1), 2) or 3). I would also be interested in EVO's performance in same situations, as I am about fed up with this phone.