A trial balloon, also known as kite-flying in the UK and elsewhere, is a term used to describe information sent out to the media in order to observe the reaction of an audience. It is a test of public opinion or reaction to a particular idea, proposal, or policy. The term is of French origin, and it translates to French ballon dessai, which was a small balloon sent up immediately before a manned ascent to determine the direction and tendency of winds. The earliest use of the term in English is figurative.

Politicians often use trial balloons in the form of an intentional news "leak" to gauge the level of support or opposition before making a final decision or taking any action. Companies also use trial balloons to judge customer reaction to a new product or service. If the coverage is favorable, the money is spent on development, but if not, the project can be canceled before consuming resources.

In summary, a trial balloon is a tentative announcement or action that is proposed to test public opinion or reaction to a particular idea, proposal, or policy. It is often used as a way to test the feasibility of a proposal and to make adjustments before it is formally introduced or presented.