Coplen v. United States

How later courts describe this case

• doctrine of equitable estoppel will be applied, in appropriate case, to prevent United States from denying existence of a contractual agreement
• warrant or exigent circumstances required for seizure of parked aircraft after officer looked in window and spotted marijuana debris
• no search to view interior of aircraft standing in public place
• interior of airplane visible from parking lot of airport
• in such cases "surveillance" might be the better word
• inapplicability of section 558(c) to failure to renew license
• inapplicability of § 558(c) to failure to renew license
• “Implied-in-fact contracts differ from contracts implied in law (quasi-contracts