New River MCAS north of TI is home to several training squadrons of the MV-22 and CH-53 (K model the new King Stallion) and I think at least the AH-1 SuperCobras (though I'm not 100% on that). So likely it is part of training should something go wrong with the airframe there is another nearby. They use all the airports around ENC for training flights and practice takeoff/landings etc. Sometimes they are in pairs and sometimes singles. For about a good 2 years they would use Greenville for training landings and takeoffs on Thursdays. So, if you forgot the day you'd know when Thursday's are, but not so much here lately. I can usually catch 2 a week now.
Regarding the OP post, I begin to worry when there's been more than 2 days with no mil flights overhead. I'm more likely to see the contract A-4s out of Kinston, the KC-130J refuelers out of Cherry Point, all the squadrons of F-15s and, KC-135s, the new KC-46s out of Semour Johnson, and now in the last 6-9 months there are 2 daily flights of USN C-2 at 21kft flying between Norfolk and Jacksonville on some sort of milk run. Last week several of the SAM aircraft (painted like Airforce 1) the C-32 (757 airframes) and C-20s (Gulfstream business jets) were in the pattern using Kinston KISO for practice.