Read the percentage carefully
RTP compares modelled returns with aggregate stakes over a large number of plays. It does not mean a particular player receives 97% of every deposit or session. A short sample can vary substantially.
SPRIBE lists 97% for Aviator. Confirm the figure in the active operator game and do not use it to infer a specific cash-out probability or next-round result.
Theoretical edge
The complement of 97% is 3%, often called the theoretical house edge. This is a long-run model concept rather than a fixed fee charged on each wager.
A headline percentage does not remove the possibility of losing the full stake on an individual round.