Also, Delta check-in, bag drop and security is often plagued by long lines so arrive early unless you have Medallion Status with Delta. Recently, Delta has improved the efficiency of the check in line but beware that you must check in at an electronic kiosk first before getting into the line.
Terminal B - Two buildings facing each other, with a parking lot in the center. Therefore, you really have two bus stops for this one terminal. American Airlines and US Airways were the major tenants but US Airways is now American. The old US Air side is renovated and roomy, with a Legal Seafood's bar in the gate area that is lively, if you can get a seat and a Fox Sports Bar. The American Airlines side now includes the gates for United Airlines, which continues to be Logan's smallest "big" tenant and has been squeezed out of Terminal C by Jetblue. The American/United side of the terminal was recently renovated inside with a number of typical fast restaurants such as Chinese, UFood Grill and Cosi. There is now a Bonfire inside as well. This side of the terminal is still a bit busy and cramped. However the security checkpoint was just upgraded and expanded, with a nice roomy atrium after the clearance point. Wait times are still long, so non-elite travelers should still leave extra time. If going through the elite security line, watch for things moving faster in the regular line and be willing to jump over. Although they generally do a good job of getting last minute arrivals checked in before flights leave, you should arrive fairly early for most flights when you are checking bags on this airline in Boston.
Terminal C - An open air single building which now hosts primarily jetblue. As Boston's largest airline by a large margin, Jetblue has thrice influenced enlargement and upgrading of the terminal. This has included continuing to renovate the two arms of the terminal past security with i-stores, a cramped but well used Legal Seafoods, and several sit down and take out places from a Brew Pub, to Wolfgang Puck, to Cosi, Boston Beer Works, and now a Wahlburgers as well. The security area was vastly upgraded to more check stations with a roomy atrium as you are being screened. While this area generally works efficiently, watch for slower lines which can sometimes not move at all for several minutes. For the most part, you will get through in a reasonably 15-20 minutes and if you are TSA-pre or a premium traveler, you will fly through in under 10. The newest change is now in the check in hall, where the Au Bon Pain has disappeared and far more stations being built for bag drop, Mosaic check in, etc. Others such as Alaska and Emirates are in this terminal as well. During busy times, the bag drop line gets long - similar to the situation at JFK Terminal 5 (lets face it jetBlue - it's not a great system).
Do note that one thing that has barely changed is the outdoor drop off and waiting area (ie - for buses, taxis and airport rides) for Terminal C is short due to the original terminal design so it is virtually impossible to wait for anyone in a car. Either you have to grab your bags fast, or you are arriving by bus.
And as of this summer, the greatest expansion in recent years at Logan Airport includes an expansion tunnel into what was once Terminal D. This expanded area of Terminal C, home to JetBlue, our largest airline tenant is the nicest part of Logan Airport. Modern charge stations, roomy waiting areas, new fast casual restaurants, including the requisite Starbucks have created a vision of what Logan could become. Along the wall you will find a history of innovation in Boston, and the most interesting upgrade is a connection to Terminal E so that passengers going overseas can transfer off JetBlue flights (note that if you are arriving International, you will have to clear CBP and Immigration first, and then redo security at Terminal C)
Terminal D - No longer really its own entity, since it had no curbside access anyway. This is now part of the extended Terminal C.
Terminal E - Terminal E remains the International terminal at Logan Airport, housing all international carriers. The growing list ranges from British Airways, Air France, Iberia, Lufthansa and Alitalia, to the newer tenants such as Emirates, Azores, Cathay Pacific (a great airline by the way), Iceland Air, Hainan and more. The check in hall is massive, so check the screens for which direction to go. Security tends to be quick because the number of flights is relatively smaller than the domestic terminals. If you eat at the cafe before the check in line, you get to the priority line so you can pass security more quickly. Inside, there are many eating options, including a new Legal Seafoods to the left. All airline lounges are at the ends of the terminal, where you need to take the elevator down.