what volcano in the U. S. poses a significant threat to air travel between North America and East Asia?

Alaska Volcano

 Observatory has issued warnings stating that either or both could erupt in the weeks or months ahead, sending ash plumes into the atmosphere and possibly disrupting air traffic between Asia and North America.

since there isn't any suggested answers i will give you the reason and hopefully you can figure it

south africa, or rather all of africa, has not been in the location in which it is nowadays throughout the geological past. after the super-continent pangaea started to break apart, gondwanaland, in which was africa, moved further south, and parts of it came to be very close to the south pole. because the climate in this part of the world is very cold due to the very dispersed sun rays in there, what is now south africa, started to freeze, and the conditions were right for the formation of glaciers. the glaciers existed up until the period when gondwanaland started to break apart and what is now africa started to move towards north, sp it warmed up and the glaciers melted.