library_construction_protocol: AEC2: processed from fresh isolate. FB: trypsinized to single-cell suspension. EC: trypsinized to single-cell suspension. Native and engineered tissues: inflated with enzyme solution containing collagenase/dispase, elastase, and DNase and incubated for 20min, then sequentially filtered. Following digestion all steps were performed on ice. Total time from tissue inflation to library preparation was <2hrs. Single-cell libraries were prepared using standard 10x Genomics protocols for v2 assay (for AEC2s and FBs), v3 assay (for native and engineered lung tissue), or v3.1 assay (for ECs)