I am a little confused because in your question is the answer. To combine the results of two queries into one query you use a Union query. The thing to remember is that each query has to have the same number and order of fields for a Union query to work properly.
If, on the other hand, that you need to combine two queries into one table, then you can create a table design, then convert the two queries into Append queries. Or make on query a Make Table query and the other one an Append query.