Sophie and Ian's online dating was essentially a modern-day version of Ted and Victoria meeting and instantly hitting it off. When long distance throws a wrench in the latter's way, they decide not to pursue their relationship. But, at the airport, Ted decides to appeal to Victoria at the last moment: maybe they could beat the odds of a long-distance relationship?
When Sophie chases Ian at the airport right before his flight and he gently turns her down, it feels like a realistic version of the decision that Ted and Victoria naively jump into. We later find out that the older Ted learns this lesson the hard way by getting Victoria's and his hearts broken. It's good to see that "HIMYF" didn't fall for the trappings of a doomed relationship, but the parallels are clearly there.
