In hybrid communication environments where both wired and wireless links exist, performance of the quality-of-service (QoS) provision can be enhanced if an application knows whether there exist wireless links in the communication channel and adapts its behavior accordingly. This paper presents a scheme using fuzzy reasoning to make applications wireless-aware. Based on the studies of statistical patterns of round-trip time (RTT) in communication sessions via wired and wireless links, the mean value and variance of RTTs are used as fuzzy inputs, and the confidence of existence of wireless links in the communication channel as the fuzzy output. Simulations and experiments show that fuzzy reasoning for wireless awareness (FuRWA) is a feasible way to enhance QoS in hybrid communication environments at the application layer. FuRWA adds intelligence into endpoints without modifying protocol stacks, and can handle scenarios where a wireless link is an intermediate component of a communication path.