Exhibit 99.1 Aspen Aerogels, Inc. Reports First Quarter 2024 Financial Results and Recent Business Highlights For Immediate Release $94.5 million in company revenue drove 37% gross profit margins and $12.9 million of Adjusted EBITDA Raising 2024 baseline Adjusted EBITDA outlook by 83% Expecting positive net income for 2024 NORTHBOROUGH, Mass., May 1, 2024 — Aspen Aerogels, Inc. (NYSE: ASPN) ("Aspen" or the "Company"), a technology leader in sustainability and electrification solutions, today announced finan ...