It felt too early for barbecue one morning at Dallas Fort Worth International Airport. I was on my way to Omaha to start a multistate barbecue tour last year when I saw a sign near gate A16 for the Salt Lick. The normal timetables for consuming food and drink seem to bend at airports. Ask anyone at a so-called Irish pub with a pint of Guinness before their 8 a.m. flight. So I pondered the breakfast taco for a moment before going right for the biggest barbecue sandwich on the Salt Lick menu.The Chop Chop ($21.99 with a side and drink) is a combination of brisket and smoked sausage chopped together and piled high on a sesame-seed bun. I got a side of slaw so…