I would bring back small liaison aircraft. Many of them. Cub, L-19-style or Helio Courier/Fieseler Storch style. STOL. Powered by kerosene burning piston engines. If you look at how simple, easy maintenance and low cost they were and compare this to today's drone infrastructure, these flying Jeeps would be good for many uses. Low technology and cheap compared to anything new. No datalinks, no jamming, no big radar return.