No, I did not misunderstand it. That it can vary the temperature by 2 degree (actually, the article rounded up, it was 1.8 degree) is a big delta and it was immediate. The observation thus shown it as an effective means of atmospheric and global temperature manipulation.
Contrail by itself will not do enough when things are averaged out - after all, the atmospheric water amount didn't change, just the distribution. And in fact, we added heat to the atmosphere by engine heat making the contrails. The only impact that could last longer than the contrail itself is the heat lost due to reflected light. If we create a thousands and thousands of say blimp like balloons using solar power to move and heat the air as it circles around... That may have a nice impact -- but plenty of studies and evaluations to be done before a judgement can be made there.
Pointing out contrail's temperature manipulation ability is just an excuse, may be... Who can resist the opportunity of mocking the Activists! (want it cooler? fly more private jets) Besides, if we do reduce Carbon Dioxide, what do we do about the plants dying? We took away their food.
Personally, I rather move to higher elevation with a greener planet than staying at our current shore line and watch the planet turn brown as plants die off. Either way, I am an old guy, so I wont be around to see whether we run out of veggie to eat, or having to swim from the house to the office to get to work.