John In Remote Kansas (JIRK) on LIK's cookie.

mousethief –

This is not an easy one to answer; but the answer comes out YES. You do need a union. Whether the monster IAM is YOUR best answer leaves me a little uncertain.
I too, was once at Boeing. As an engineer, I can assure you that being a union member at Boeing does not take away any professionalism you may possess, and does not make you any more of "an hourly worker" than the company already considers you to be. I'm sure you already fill out a time card. You are probably classified as a "salaried exempt" employee – that will not change. (Ask me later what you're exempt from.)
I joined Boeing in Wichita many years ago, when we had our own local union. Officers were elected from the membership, and were unpaid. The only compensation they got was that Boeing (per the contract) paid them their regular salary while they were conducting union business, and excused them from regular duties (sometimes grudgingly) for union business.
I was a member of my union's (5 person) executive committee for a time. In this capacity I had a thorough education in the kinds of things that the union can do, and needs to do, to benefit the members. I also learned a lot about the kinds of things the company is willing to do to people "to benefit the bottom line."
Unfortunately, the great majority of the membership seemed to think that "the union," which they considered some sort of paid hired help, should do it all for them. It was very difficult to get people to participate – although they were all quite willing to complain.
The local engineers' union affiliated with the Seattle monster union (SPEEA), and personal representation died. The residual benefits – a contract, with some enforcement – were still worth a lot, BUT ---. (The good old days are gone, forever??)
Without a union, you have no contract with the company. You are "an employee at will of the company." They can do anything they want to (and probably will eventually) – and they are under no obligation to treat you the same as they treat everyone else. Get a contract.
Boeing management is not responsible to you. Their only concern is with making the stockholders happy. The union is responsible to you – although whether it will make you happy depends on whether you and all of your fellow members will give it the support necessary.
Having a union rep is a little like having a congressman working for you. Ya gotta watch 'em all the time – but if everybody else has one, don't you need one too?