I have been doing some research on locust trees lately (and off and on over the past year). There are varieties that are thornless. There are also varieties that are both thornless and seedless/podless. I believe that these podless ones may also be bloomless. Have your honey locusts bloomed in the past and just did not this year, or have you ever seen them bloom?
The podless varieties are some of the "ornamentals" that have pretty Spring leaves. They start out looking like Autumn leaves, coming out with some yellow in them, and then going green before eventually going yellow again in Autumn.
We have some here in town that are thornless but produce many pods. That is where I get my seeds from.

We also have some at work that are thornless and podless. These do not bloom like a honey or black locust normally would. I think they must sometimes produce a few flowers as they do sometimes produce a pod or two, but I have never actually seen them flower.