Last month, JetBlue Airways (NASDAQ:JBLU) gave its clearest indication yet that the future of its Embraer (NYSE:ERJ) E190 fleet is in doubt. JetBlue's new CFO, Steve Priest, has ordered a thorough fleet review that includes deciding whether there is still a place for the E190 at JetBlue.

Early retirement of the E190 fleet is a very likely outcome of this review. JetBlue's E190s have been expensive to maintain almost from day one, and maintenance costs will only rise as the planes age. However, Embraer still has a good chance to keep JetBlue's business, by upgrading the carrier's E190 fleet to its next-generation E2-series jets.

The E190 fleet isn't built to last

While the E190 jet was quite popular in its first few years on the market, it has fallen out of favor in recent years. American Airlines, the only other major E190 operator in the U.S., has already announced plans to retire its last E190s by the end of 2019, even though those planes are currently less than 10 years old on average.

American Airlines says it has accelerated the retirement of its Embraer fleet due to expensive maintenance checks that are coming up. JetBlue has had just as much trouble with its E190 maintenance costs, with the engines being particularly problematic.

For the time being, JetBlue is more or less locked into its Embraer fleet. Half of its E190s are on long-term leases that expire between 2023 and 2025. The other half are owned, giving JetBlue more flexibility. Still, JetBlue just signed a five-year maintenance agreement for its E190 fleet a few months ago, indicating that it's not planning any big changes in the near future.

On the other hand, it seems equally unlikely that JetBlue will keep its E190s until they reach the standard retirement age of 25 in the mid-2030s. JetBlue says that unit costs for its E190s are about 20% higher than for its A320 fleet, adjusted for stage length (the distance covered by an average trip). That gap will only widen over time as JetBlue adds seats to its A320s and as the E190s age, requiring even more maintenance work.

But Embraer's next-generation jets look like a good solution

While JetBlue isn't satisfied with the performance of its E190 fleet, it operates numerous high-frequency, short-haul routes -- primarily in the Northeast -- that are ideally suited for a plane of that size. Some of those routes are among the company's most profitable. Thus, returning to a single fleet type of Airbus planes is not a very realistic option.

By contrast, Embraer's upgraded E-Jets, which are scheduled for delivery to customers beginning in 2018, could be a very good replacement option.

Embraer has stated that its E2-series jets will offer double-digit maintenance cost savings over their first-generation counterparts, along with higher reliability. Furthermore, the E190-E2 will use 16% less fuel per seat than the E190. The larger E195-E2 will be even better, burning 24% less fuel per seat than the E195 (which itself is slightly more fuel-efficient than the E190).

If Embraer's E2-series jets meet expectations, then the current 20% unit cost disadvantage relative to the A320 will shrink dramatically. The E195-E2 would offer a particularly good balance of small size (keeping trip costs low) and low unit costs.

The stakes are high for Embraer

JetBlue has been one of Embraer's biggest customers over the past 12 years, but it hasn't added any E190s to its fleet since 2013. It has another 24 E190s on order, scheduled for delivery between 2020 and 2022. However, if anything, JetBlue is likely to convert those orders to the E190-E2. It wouldn't make sense to buy more first-generation E190s at that point.

For Embraer, it is critically important to make sure that JetBlue follows through with those orders. (And ideally, that it replaces its entire E190 fleet!) While the E2-series jets look good on paper, they have sold slowly so far. Of the 275 firm orders on the books, less than half seem solid based on current industry conditions. A JetBlue deal would give Embraer's order book a big lift.

Embraer is relatively well positioned to win JetBlue's business. For example, it can apply any deposits from JetBlue's current E190 order to a future E2 order and it could offer to buy back JetBlue's 30 owned E190s to facilitate a deal. Those planes could either be resold to other E-Jet operators or stripped for parts to support Embraer's services business.

JetBlue certainly may be wary of doubling down on Embraer jets due to its disappointing experience with the E190. But with the right combination of pricing and performance guarantees, Embraer could still snatch victory from the jaws of defeat.