This paper investigates the uncertainty in formation management in emergency path planning via probability and imprecise probability methods. When in-flight failures or damage occur resulting in a distress condition, rapid and precise decision-making under imprecise information is required in order to regain and maintain control of the aircraft. In order to fly the pre-planned aircraft trajectory and complete safe landing, the uncertainties in system dynamics of the damaged aircraft need to be estimated and incorporated at the level of motion re-planning. The damaged aircraft is simulated via a simplified kinematic model. The different sources and perspectives of uncertainties in the damage assessment process and post-distress trajectory re-planning are presented. The objective of the trajectory re-planning is to arrive at a target position while maximizing the safety of the aircraft given uncertain conditions. Comparative analysis between Bayesian and Dempster-Shafer evidence theory is presented for analyzing imprecise  information. Simulations that take into account aircraft dynamics, path complexity, distance to landing site, runway characteristics, and subjective human decision are presented for motion planning and landing of an aircraft following a hypothetical distress event.