leave (one) hanging
1. To withhold information from one when it is expected to be delivered. Hey, don't leave me hanging—did you get the job or not?
2. To leave one in an unsettled state or without some kind of resolution. The consultants were supposed to deliver the report last week, but they've kind of left us hanging.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
leave someone or something hanging (in midair)and keep someone or something hanging (in midair)
1. Lit. to keep someone or something suspended in midair when support for the person or thing is removed. The ladder collapsed and left me hanging in midair. Fortunately, I grabbed onto the windowsill.
2. Fig. to suspend dealing with someone or something; to leave someone or something waiting to be finished or continued. She left her sentence hanging in midair. Tell me the rest of the story. Don't leave me hanging in midair.
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.
Also, leave hanging in the air or in midair . Keep undecided, uncertain, or in suspense. For example, Since we hadn't found a big enough hall, we left the final date hanging, or She couldn't figure out a good ending for the book, so her audience was left hanging in midair .
The American Heritage® Dictionary of Idioms by Christine Ammer. Copyright © 2003, 1997 by The Christine Ammer 1992 Trust. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.