The Russian Air Force has reportedly significantly expanded the size of its sole squadron of Su-57 fifth generation fighters, adding four new aircraft to the unit following the largest delivery of serial production airframes to date. This follows a smaller delivery of two airframes in May, with batches expected to continue to grow in size over the next three years. 22 more aircraft are expected to be delivered over the next 24 months bringing the fleet size to 32 by the beginning of 2024, with further expansion of production facilitating fleet growth to 76 airframes three years later. Airframes will be delivered at an average rate of 1.125 per month in the 36 months from January 2024, compared to 0.5 per month in 2022. The scale of production at the end of the decade will nevertheless be very significantly smaller than that which the rival Chinese J-20 and American F-35 have long since already reached. The possibility remains that more than the76 Su-57 airframes will have been built by the end of 2027, but that a portion of these are being reserved to meet export orders. The Su-57 is the only post fourth generation fighter produced outside China and the United States, and stands out from its competitors for a number of its advanced features including use of a unique laser defence system, integration of sextuple radars, and access to APAA guided R-77M air to air missiles. The sole operational Su-57 unit has already carried out multiple combat operations over Ukraine including air defence suppression missions, with unverified reports indicating it may have been involved in an air to air engagement. No other fighter of its generation has been deployed for comparable operations.