I'm afraid you're right, but I'm also afraid that no one has the necessary combination of money, technological skill and military might to undertake that kind of geoengineering unilaterally.
They point out the plan assumes you can launch planes from a few different points around the globe. You don’t need global agreement, but at least access to some foreign airports.
An utterly meaningless comparison. None of those countries are going to simply stop spending all of their money on their military overnight.