It was a Boston-Minneapolis flight that had to divert to Pease Tradeport in New Hampshire, along the coast. There was the now-common 'smoke in the cockpit' precautionary landing. Why Pease instead of back to Boston? My guess is because they could hop up the coast to Pease and land at their 11,000+ foot runway quicker than they could navigate thru the Boston air traffic. Besides, outbound flights from Boston go up along the north shore anyway so as not to mix with the incoming flights from the west.