Anyone use Xometry for Aerospace Parts?

I had a couple lightweight, thin-wall aluminum DMLS part made by Xometry for an unmanned aircraft application, and they did a very nice job. Passed dimensional and dye pen inspection requirements. However, you will need to talk to Xometry about your specific application requirements. Put together a detailed procurement spec for the part you want Xometry to supply, and they'll let you know if they can do it.

I assume you mean something 3D printed, like SLS or FDM.

The results remain, and probably will be forever, process and procedure-dependent. Use the machine wrong, and the part will be far to brittle (poor cohesion) or underfilled or something else unacceptable to you. Know what you need to specify to get the results you want. Dimensions are not the only measure of success.

I tested many of my ideas on a FDM machine when I had access to one for a project several years ago. Later I had a detailed conversation with Stratasys on the matter, and their representative answered my questions very thoroughly. If I were to make a recommendation, I would start with them, and compare Xometry on that basis.