Suddenly, everywhere you look, there's a Northrop Grumman (NYSE:NOC) Fire Scout drone helicopter buzzing around.

Since its inception more than a decade ago as an "RQ-8A" flying robot built on a Schweizer Aircraft chassis, Northrop's MQ-8B drone helicopter has only gotten bigger -- and better. To date, the MQ-8B configuration Fire Scout has logged more than 14,000 flight hours across 5,300 sorties.

Fire Scout has interdicted drugs while deployed on the U.S. Navy frigate USS McInerney, and tracked pirate ships in the Gulf of Aden, operating off the USS Halyburton. It has monitored militants in Afghanistan and test-fired rockets, foreshadowing a day when the unarmed spy-bird might pack heat of its own.

Earlier this month, the Navy's favorite drone helicopter celebrated two new developments. In an interdisciplinary leap, it joined the Coast Guard for a term of service aboard the national security cutter USCGC Bertholf. One week later, the Navy put an even more advanced version of the Fire Scout through its paces, when an MQ-8C-version Fire Scout began operating off the guided missile destroyer USS Jason Dunham.

According to George Vardoulakis, Northrop Grumman vice president for medium range tactical systems, these tests will continue through summer 2015, ending with the MQ-8C being declared "ready for operations by year's end."

What it means to Northrop Grumman

It's hard to say which of these developments is more significant for Northrop Grumman -- both could be key. On the one hand, expansion of Fire Scout use to the Coast Guard opens up a new market for Northrop Grumman, potentially permitting additional sales. On the other, well...

As of 2011, the Navy alone planned to order as many as 168 MQ-8B drone helicopters, working out to an estimated $5.6 billion in revenue for Northrop. For context, Northrop brings in just south of $25 billion a year in sales. Improvements built into the MQ-8C model (now built upon a Textron (NYSE:TXT) Bell 407 chassis), however, enable this latest model to fly nearly twice as long as its predecessor, carry three times more surveillance equipment, and generally do more work with fewer 'copters.

As a result, the Navy has determined it might not need to buy quite so many drone helicopters. Current plans call for purchasing 70 MQ-8Cs and a few dozen MQ-8Bs. When all is said and done, this should put just under 120 Fire Scouts in service with the Navy.

That still would make the Fire Scout far and away the most successful drone helicopter in U.S. service. Other defense contractors have produced helicopter drones of their own, such as the:

K-MAX, built by Lockheed Martin NYSE:LMT)

Boeing 's NYSE:BA) Hummingbird (terminated by the Army in 2012); and

's Hummingbird (terminated by the Army in 2012); and United Technologies' NYSE:RTX)

But to date, none of these has enjoyed the sales success of Northrop Grumman's Fire Scout drone helicopter.

What it means to investors

At an estimated cost of $33 million per MQ-8C, versus just $16 million per MQ-8B, simply selling fewer Fire Scouts need not mean significant lost revenue to Northrop Grumman. Also, according to S&P Capital IQ, Northrop earns a 12% operating profit margin at its aerospace systems division (which builds the Fire Scout). So those profits should be largely secure.

That said, it's crucial that Northrop's test flights of the MQ-8C model Fire Scout work out well. And it wouldn't hurt for Northrop to win the U.S. Coast Guard as a client. The more Fire Scouts buzzing over the water, the more buzz for Northrop Grumman as the nation's premier drone helicopter producer.