CHICAGO (WLS) -- Four Chicago area families with seriously ill children are headed to Arizona to check out the Cubs during spring training."We have special guests joining us on the flight to Arizona today. Let's give them a warm welcome," said the American Airlines ticket agent.Most of the people going on the trip have never been to Arizona before, and none has ever seen the Cubs in spring training. But that is changing as of Monday.The patients suffering from serious medical conditions ranging from cancer to heart trouble are in for the trip of a lifetime."I'm pumped. It's great!" said Zach Lum, who lost his leg after being diagnosed with cancer last year.His mother, Donna Potts said, "It's been a challenging nine months, but the right attitude makes it go a lot easier."Doctors chose Zach and three other patients for this trip. American Airlines is providing transportation and Sheraton Hotels will put them up.Each of the patients is accompanied by family members and best friend. They will get to spend time with the Cubs players on the field and in the locker room, not a hospital room.Dr. Frank Belmonte, the head of Pediatrics at Advocate Children's Hospital said, "It just means the world to them and to us to see them have a good time and get to be a normal kid. It's gonna be great."Fortunately, all four patients are die-hard Cubs fans. Allen Hermeling with the Chicago Cubs says the team really enjoys doing this."It's really something that lifts up our spirits as much as it lifts up theirs," said Hermeling.Before boarding, they each get a backpack full of goodies including hats and t-shirts. The full team reports to camp on Monday and this group will spend the entire day at the ballpark on Tuesday.