The Big Bang Theory Episode 7.17 The Friendship Turbulence

Wolowitz attempts to mend his strained friendship with Sheldon by inviting him on a trip to Houston to see NASA. Sheldon gladly accepts and they try their best to avoid insulting or irritating one another, but they end up fighting while onboard the plane, only to be brought back together as the plane hits a very rough patch of turbulence. Meanwhile, Penny's car breaks down and she fears she'll have to go back to waitressing, so Leonard surprises her and buys her a used car so she can still go to auditions. Koothrappali also gets upset with Amy when she tries to help him woo a woman on an online dating site and she winds up having more in common with her than he does.