While the F105 Thunderchief was the USAF's principal strike weapon during the Rolling Thunder campaign, the US Navy relied on the Douglas A-4 Skyhawk for the majority of its strikes on North Vietnam. The Skyhawk entered service in 1956 and remained in continuous production for 26 years. Throughout Operation Rolling Thunder it was the US Navy's principal daytime light strike bomber, remaining in use after its replacement, the more sophisticated A-7 Corsair II, began to appear in December 1967.