Dramatic changes to aircraft design are on the horizon to meet ambitious efficiency and emissions targets. This will bring about changes in the role and design of aero-engines, requiring a greater degree of high fidelity, coupled modelling. To bridge a wide range of spatial and temporal scales, modern turbomachinery design employs a wide range of modelling fidelities during different design stages and for different engine components. High fidelity methods such as Large Eddy Simulation (LES) have been successfully applied to numerous complex flows where traditional Reynolds-Averaged Navier-Stokes (RANS) modelling does not sufficiently represent flow physics to be consistently accurate. Using LES and, for high Reynolds number flows, hybrid LES-RANS, critical knowledge has been extracted and exploited both to inform designs and to improve lower order modelling. It seems certain that uptake of high fidelity methods will continue at a rapid pace. Here we explore some of the future challenges facing turbomachinery simulation using LES. These include use of higher order schemes, internal and external zonalisation and coupling, exploitation of hardware and pre and post-processing. Although these pose technological barriers, these will enable unexplored design space to be traversed with confidence, resulting in cleaner, quieter, and more efficient aircraft. © 2019 The Authors