The top flying ace of the Finnish Air Force, he led all Finnish pilots in score against Soviet aircraft in World War II (1939–40 and 1941–44), with 94 confirmed aerial combat victories (he himself claimed further kills for a total of 126 victories, but these were unconfirmed) in 437 sorties.

He finished the war without a single hit to his plane from enemy fighter airplanes (once he was forced to land after a friendly anti-aircraft gun fired at his Bf 109).

On 21 July 1941, Juutilainen and five other Buffaloes scrambled to intercept Soviet fighters from 65th ShAP that were strafing Finnish troops near Käkisalmi.

[7] A few days later, on 1 August, seven fighters under the command of First Lieutenant Karhunen destroyed six I-16s near Rautjärvi, and Juutilainen (having been promoted to Warrant Officer in the meantime) claimed two of them.

[8] On the morning of 6 February 1942, while reconnoitering the Petrovkiy-Jam region with other LLv 24 pilots, Juutilainen intercepted seven Tupolev SB bombers escorted by 12 MiG-3s.

As we intercepted the Soviet aircraft, I spotted a formation of three SBs heading for a nearby railway line and dived after them.

In spite of the threat posed by the latter, I managed to hit the bomber in the starboard engine, which poured out smoke and oil.

[9]On 27–28 March 1942, 3/LLv 24 moved to Immola in preparation for a Finnish Army offensive on Suursaari, in the Gulf of Finland.

Although grossly outnumbered over the Gulf of Finland, LeLv 24 pilots were more experienced than their Soviet opponents from Red Banner Baltic Fleet.

[10] On 28 March, WO Juutilainen, in patrol with Sgt Huotari, attacked some "Chaikas" of 11 IAP over the Suurkylä shoreline, at Hogland, and shot down two of them.