\section{Introduction}
\textsc{[todo]} Motivate the growth of urban freight and the last mile as the dominant cost and
emission bottleneck. Justify treating UAV-based and truck-based urban logistics as two
independent lines of study rather than as a single integrated architecture.

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\noindent\textbf{Research gap.} \textsc{[todo]} State precisely what a systematic review of this
scope contributes over existing narrative reviews of drone delivery and of urban freight
routing.