⚡️The energy shock is beginning to ration real economic activity. Airlines sit close to the physical edge of the economy because fuel is one of their largest variable costs and they cannot manufacture their way around it. When jet fuel gets expensive enough, there comes a point where raising fares no longer solves the problem. Higher fares destroy demand. Lower fares destroy margins. Then capacity gets cut. That is the transition worth watching. Once an airline begins cancelling economically marginal flights because fuel makes the route unattractive, the oil shock has escaped the commodity screen. It is now deciding which pieces of the economy are allowed to happen. Fewer flights means fewer seats. Fewer seats means higher fares on surviving routes. Higher fares mean fewer discretionary trips. Fewer trips hit hotels, restaurants, conferences, tourism, regional airports, rental cars, and every local economy attached to human movement. The shock propagates. And aviation could simply be the first highly visible layer. Trucking feels diesel. Agriculture feels diesel and fertilizer. Manufacturing feels freight and feedstocks. Utilities feel fuel. Consumers feel gasoline and electricity. Eventually the entire economy starts reorganizing around an expensive energy constraint. That is where the macro becomes genuinely dangerous. Physical scarcity starts doing the tightening before the Fed does. Real household income gets squeezed. Corporate margins get squeezed. Demand begins weakening. Yet headline inflation stays elevated because energy is still expensive. That traps monetary policy. Cut too early and inflation credibility gets hit. Hold rates high and the energy shock keeps chewing through growth. Hike further and demand gets crushed faster while no additional barrel of jet fuel appears. This is the stagflation transmission mechanism in its cleanest form. The deeper shift is that the economy may be moving from a regime where money was the dominant constraint to one where physical throughput becomes the constraint. For years, cheap capital could smooth almost everything. Expensive fuel does not care how low the discount rate is if the barrel is unavailable or structurally costly. That is why this United comment matters more than it looks. If airlines are already contemplating pruning December schedules, the system is beginning to choose which movement is still worth the energy required to produce it. That is rationing. And once energy begins rationing mobility, the inflation story has crossed into the real economy in a much more consequential way.