Aerospace material Inconel 718 is well known for its poor machinability. This article presents an experimental study of the cutting forces in high-speed dry milling of Inconel 718 using a milling cutter with coated carbide inserts. An assessment of the cutting force variations is conducted using statistical approaches and wavelet decomposition taking into consideration the dynamic effects. The averaged peak force values, the peak force variation range and distribution, and the skewness are evaluated. It shows that cutting speed does not have a significant influence on the averaged peak cutting force for the range tested. The tool–workpiece vibrations at the cutter entry stage and exit stage are generally more significant. Moreover, wavelet packet decomposition at level 3 with the DB4 wavelet and Shannon entropy is found to be an effective approach to identify the chatter onset.