Boeing (BA) shares have defied gravity for months, rising a whopping 70% during the past year to hit record highs of more than $117. What’s even more remarkable — those gains came despite the 787 fleet’s battery fire-related grounding in January, the Pentagon’s budget and sequestration cuts, as well and a third — apparently unrelated — Dreamliner fire onboard an Ethiopian Airlines jet in July.

But while Wall Street finds a lot to love about BA — and its long-term value is readily apparent — investors could be well-served to look for the stock to retreat slightly from these lofty levels before they buy.

Let’s get to the good news first. Here are three factors that should further fuel BA’s rise through the clouds:

The Bigger Dreamliner Prepares for Takeoff: Boeing’s larger Dreamliner, the 787-9, was scheduled to take to the skies for its maiden flight today — a critical step in ensuring that the innovative carbon-composite jet is ready for delivery to Air New Zealand in mid-2014. The stretch Dreamliner is 20 feet longer than the original, and will carry about 40 more passengers 300 nautical miles farther than the 787-8. Successful test flights are a big deal for any aircraft program, but particularly so for the 787, which can’t afford production delays to iron out any kinks.

International Defense Opportunities: Pentagon cuts and sequestration might have dampened defense contracting opportunities, but fortunately for Boeing, the U.S. is not the only game in town. Growth in international sales has been a boon for BA — and international sales account for 30% of the company’s defense revenues. The market has been optimistic this week that BA’s F-15 Silent Eagle will win a $7.6 billion fighter deal with South Korea. According to published reports, competitive bids from Lockheed Martin’s (LMT) F-35 and Eurofighter’s Typhoon came in over budget.

Plane Deal With Lufthansa — and the First Sale of 777X: Lufthansa is expected to move forward on an order for 50 wide-body aircraft worth $10 billion this week, splitting the purchase between Airbus’ (EADSY) A350, which made its maiden flight in June, and BA’s soon-to-be launched 777X. The move, if approved by Lufthansa’s board this week, would make the German flag carrier a launch customer for the next generation of Boeing’s 777 mini-jumbo — a plane expected to roll off the production line by the end of the decade. Such a deal would give BA a boost, particularly since Airbus snagged a 100-plane narrow-body deal with Lufthansa back in March.

These factors make a strong argument for a continued rise in Boeing’s fortunes. But at this altitude, it wouldn’t take much to trigger a correction, so investors should keep an eye on two areas: additional defense budget pressure and new (or more serious) 787 Dreamliner glitches.

Boeing Chairman and CEO James McNerney pointed to some of the challenges in the defense and space systems group at the Morgan Stanley Industrials & Autos conference on Monday. While he noted that the fiscal 2014 Congressional budget markups are “relatively favorable” to Boeing’s key programs, neither President Obama’s budget request — nor current Congressional proposals — reflect sequestration level spending limits yet.

With regard to the Dreamliner, the innovative jet continues to struggle with so-called “teething problems.” On Sunday, a 787-8 operated by Norwegian Air Shuttle had to leave behind 70 of the 250 ticketed passengers booked from New York to Oslo when a hydraulic pump on the plane indicated it couldn’t accommodate the weight of the full passenger load.

Longer-range competitive challenges — particularly in the narrow-body jet market — bear watching as well. Monday’s maiden flight of Canada-based Bombardier’s new CSeries 100 ups the ante in a niche where Airbus’ A320neo, BA’s future 737 Max and the Commercial Aircraft Corporation of China’s C919 will battle for market share in the next generation of airline workhorses.

Bottom Line

BA shares have flouted doomsayers’ predictions in recent months, rewarding shareholders who believed the stock’s meteoric rise this year was sustainable. Meanwhile, the 787-9 and other factors look poised to give more long-term

That said, Boeing will need to take a breather sooner rather than later — and when it does, that could be a good time for investors to move.

As of this writing, Susan J. Aluise did not hold a position in any of the aforementioned securities.