Most of the gains are from speculators closing out their short positions. Many of them probably had triggers around the $1 mark, but the sheer volume of shorts closing was enough to bounce the price significantly. It will probably continue for a few more days and then show the expected decline.
UAL stock is worthless. Whatever way you look at it, there is no way they can emerge from Chapter 11 without either invalidating or severely diluting the equity.
"The A340-300 may boast a long range, but the A340 is underpowered" -- Robert Milton, CEO - Air Canada