The 737-300/400/500s of UA and US have different panel configurations. UA's fleet is mostly glass cockpit, whereas US' fleet have traditional instrumentation. Would this be a problem for the pilots? Would UA upgrade ex-US 737s to glass cockpit configuration? Wouldn't that be too expensive?
The classic 737 was not available with glass cockpit, perhaps you are referring to the EIS engine display vs.electromechanicl engine instruments. Most airlines that received aircraft over a longer period of time have fleets with both setups and there are only minor pilot training differences. The same sensors are used for both the conventional and EIS indicating systems. The advantage of EIS is that there are only two display units to maintain Vs. 19 gauges exposed to possible failure. (they also use less power,have almost no moving parts, detects and indicates abnormal starts, and records exceedance info.
UA's 737-300/-500 fleet does in fact have EFIS ("glass") cockpits, I would not see United upgrading the cockpits of USAirways jets as they also have -400s. What I see United doing is segregating the pilots for each of the separate companies (at least until they move up to the next aircraft type).
You're right, 3/4/500 does have EFIS, I was thinking EICAS vs. EIS and the differences on the 3/4/500, I stand corrected. The -200 will of course be a seperate qualification, I believe both airlines fly -200s.