Earlier today we got news that United’s flight attendants had ratified a contract. It was a close vote — 90% of flight attendants cast ballots and only 53% of those voted in favor. But it lets the airline move forward combining the legacy United and legacy Continental flight attendant groups as one.

As I wrote at the time, United will finally be one airline in the sky. From a customer-facing standpoint that will complete the merger.

But the airline’s work isn’t done, even with that. United has been working for years on a contract with mechanics. Earlier this year the Teamsters voted down a contract with 93% of ballots against.

When United unveiled its plan to improve financial performance in June CEO Oscar Munoz described improved efficiency of working off of a single maintenance system as key to that plan. That will improve operational reliability and reduce cost.

Now United and the Teamsters, representing 9000 employees, have reached an agreement. This is the last work group without a contract, and one that earlier in the year had been rumbling about a strike.

• The agreement still has to be ratified.

• Members who were vocally opposed to the last deal will have to be sold on this new one.

But United is clearly making progress. Winning over employees — even more than winning over customers — has seemed to be the key strategy that new CEO Oscar Munoz has deployed as he’s tried to turn around the airline (the charm offensive hasn’t stopped new restrictions on award tickets or plans for basic economy).

Happy, effective employees and new premium cabins, lounges and amenities will ultimately do more than stroopwafels and illy coffee. But those symbolic changes had to come first, and a consistent new business seat is still years away from being rolled out across the fleet.

If the Teamsters vote to ratify, the building blocks will appear to be in place — albeit at higher costs at a time when challenges across the industry are on the revenue side.