Well, a key question is "Where?" is the airplane to be located? USAAF fighters sent to the ETO were equipped with the British designed SCR-522 radio as soon as they got there. They had to be compatible with what the RAF was using or else risk getting their arse shot off. The SCR-522 gave 4 VHF channels, each selected by just a push button. This was a great advancement and pretty quickly became the standard.
By the way, that standardization included the IFF equipment. A new very sophisticated UHF IFF set was developed by the US, called the BC-645. It even allowed aircraft to interrogate each other as well as the ground air defense system to interrogate aircraft. But the RAF would not change their system, so the BC-645 could not be used. By the end of WWII the BC-645 was obsolete so those sets got sold as surplus to ham radio operators for the next 40 years.
The standard fighter radio for both the USAAF and USN in 1942 was the ARA and ATA for the USN and SCR-274-N for the USAAF. These systems featured individual transmitters and receivers for each channel and were HF, using the range 3 to 9 MHZ and were so similar that many of the subassemblies were interchangeable. The USN had additional frequency areas covered by using some sets that were unique to the Navy but that would have worked in USAAF aircraft had they just plugged them in.
The SCR-274-N fit well with the way air traffic control was done in the USA, since it featured a receiver capable of tuning in the Adcock ranges and airfield control towers. So you see SCR-274-N installed in P-38's in the USA and SCr-522 installed in P-38's in the ETO and probably the Med as well. That photo shows an SCR-522 installed in a F-4 photo recon Lightning in the ETO but we have pictures of the same type of airplane in the same time frame in the USA equipped with SCR-274-N. As it turned out, the SCR-274-N installed in the P-51A was very useful for the Air Commandos in Burma because they could talk directly to the ground troops, who did not have suitable VHF sets but they began using SCR-522 in the Pacific as well.
The USN developed the ARA/ATA sets into the ARC-5, which offered the option to have both HF and VHF communications.