An air containment system comprising: a plurality of panel assemblies (22,100) configured to be arranged in side-to-side relation to form a ceiling, each panel assembly (22,100) including a flexible panel (24,102) having a first end, a second opposite end, a first side (30,108) and a second opposite side (32,110), a first end connector (50,114) configured to secure the first end of the flexible panel, and a second end connector (52,114) configured to secure the second end of the flexible panel (24,102), characterised in that the air containment system is configured to enclose a hot or cold aisle of a data center defined by a first row of equipment racks provided on one side of an aisle and a second row of equipment racks provided on an opposite side of an aisle, the flexible panel (24,102) having a widthwise dimension approximately equal to a widthwise dimension of a rack and a lengthwise dimension sufficient to span across the aisle, said first end connector (50,114) being configured to secure the first end of the flexible panel (24,102) to a rack provided on one side of the aisle and said second end connector (52,114) being configured to secure the second end of the flexible panel (24,102) to a rack provided on an opposite side of the aisle. a plurality of panel assemblies (22,100) configured to be arranged in side-to-side relation to form a ceiling, each panel assembly (22,100) including a flexible panel (24,102) having a first end, a second opposite end, a first side (30,108) and a second opposite side (32,110), a first end connector (50,114) configured to secure the first end of the flexible panel, and a second end connector (52,114) configured to secure the second end of the flexible panel (24,102), characterised in that the air containment system is configured to enclose a hot or cold aisle of a data center defined by a first row of equipment racks provided on one side of an aisle and a second row of equipment racks provided on an opposite side of an aisle, the flexible panel (24,102) having a widthwise dimension approximately equal to a widthwise dimension of a rack and a lengthwise dimension sufficient to span across the aisle, said first end connector (50,114) being configured to secure the first end of the flexible panel (24,102) to a rack provided on one side of the aisle and said second end connector (52,114) being configured to secure the second end of the flexible panel (24,102) to a rack provided on an opposite side of the aisle. a flexible panel (24,102) having a first end, a second opposite end, a first side (30,108) and a second opposite side (32,110), a first end connector (50,114) configured to secure the first end of the flexible panel, and a second end connector (52,114) configured to secure the second end of the flexible panel (24,102), characterised in that the air containment system is configured to enclose a hot or cold aisle of a data center defined by a first row of equipment racks provided on one side of an aisle and a second row of equipment racks provided on an opposite side of an aisle, the flexible panel (24,102) having a widthwise dimension approximately equal to a widthwise dimension of a rack and a lengthwise dimension sufficient to span across the aisle, said first end connector (50,114) being configured to secure the first end of the flexible panel (24,102) to a rack provided on one side of the aisle and said second end connector (52,114) being configured to secure the second end of the flexible panel (24,102) to a rack provided on an opposite side of the aisle.