"Hi, Jack" is the 16th and final episode of LOST's 7th season.
The name is a pun on "hijack", and the episode takes place right after episode 15 ended. Jackface, having killed all his victims and enemies over the season, boards a full airplane which he hijacks mid-air. He flies it towards the island and after a fight for the controls the plane crashes on the island as the frame goes black, setting the scene for an 8th season.
The eight season has been promised by the producers to be "even more mind-boggling, action-filled, ridiculous, emotional and leave even more mysteries unsolved than all the other seasons combined".