What is the most probable relationship between Tom and Jack?

W: I often mistake Tom for Jack. Can you tell them apart?
M: No, they look so much alike that they even confused their mother sometimes when they were young.

M: Excuse me, I have a ticket for the 6 o’clock flight to London. But I’m afraid I can’t make it. Is there a seat available for tomorrow morning?
W: Let me see. I’m sorry. All the morning flights have been booked up. The earliest we can get for you is the 2 o’clock flight in the afternoon.