WASHINGTON--Air Force One--the plane with President Obama on board-- aborted an attempted landing at a Connecticut airport. The plane landed at Bradley International Airport after a second attempt, according to pool reports.

UPDATE
from White House Spokesman Nick Shapiro:

AF1 did a go-round at Bradley Intl Airport this morning because of weather. They circled around and landed safely a few minutes later, at 10:05 a.m.

The pilot was in the process of landing but due to weather the pilot decided to circle around and then landed the plane, this is a standard and safe procedure.